• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.219-221
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• 2000

본 논문은 객체 관계형 실시간 DBMS인 Tachyon이 제공하는 데이터 타입과 객체지향 질의의 설계 및 구현을 기술한다. Tachyon은 고성능 데이터 처리를 지원하는 객체 관계형 메모리상주 데이터베이스 시스템(Main-memory resident ORDBMS)로 Tachyon의 데이터 타입과 SQL은 ANSI SQL 3 draft를 기반으로 설계되었으며, 객체 관계형 질의 처리를 위한 OID 데이터 타입을 추가하였다. Tachyon은 클래스 간의 수직적 관계(상속)와 수평적 관계를 정의하고 조작할 수 있는 객체지향 질의를 통하여 융통성있는 데이터 조작이 가능하며, OID를 기반으로 경로식(path expression)을 이용한 향해 질의(navigational query)를 통하여 죠인(join) 비용을 절감하고, index를 통한 인스턴스 접근 등을 통하여 효율적인 데이터베이스 접근을 시도할 수 있다.

• Journal of the Korean Institute of Navigation
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• v.25 no.3
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• pp.225-236
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• 2001

In the recent years, major ship registers have demanded improved safety on the hull stress of large bulk carriers which are on navigation or cargo handling in harbour. Under these circumstances, a system that monitors hull stress and ship condition is being more and more important. If efficient and appropriate navigational information is given, safety of navigation would be greatly improved. The major ship registers of the globe are investing a great effort on the development of a system that monitors the hull stress of ship. Using this system, information of hull stress and ship motion is given to the users and also the data is stored on the external data storage system simultaneously. Through this study, a software that monitors hull stress was developed. Not only can randomized input-data of the standard hardwares be applied to the system, but also this system can be operated on and applied to real hardware systems.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.361-363
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• 2003

항해는 웹 응용의 중요한 특징 중 하나이다. 사용자는 인터넷에서 더욱 자유롭게 응용 내를 이동하고 하나의 웹 응용을 통해 다른 웹 응용을 사용하기도 한다. 웹 응용의 중요성이 커지고 있으며 사용자는 웹 응용이 더욱 정확하게 동작하고 그 것을 통해 더 자유로운 항해를 할 수 있기를 요구한다. 이런 환경에서 더 짧은 개발 기간에 더 정확한 동작을 하는 웹 응용의 개발이 요구되고 있다. 하지만 개발자들은 개발, 구현에만 집중하고 테스트를 소홀히 하는 경향이 강하다. 기존의 웹 응용 테스트에 관한 연구는 웹 응용의 기능 테스트를 중심으로 진행되어 왔다. 본 논문에서는 웹 응용의 효과적인 테스트를 위해 항해 구조를 이용한 테스트 케이스 생성 방법을 제안하고 이를 이용한 항해 테스트 방법을 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.47-49
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• 2022

Robot navigation has seen a major improvement since the the rediscovery of the potential of Artificial Intelligence (AI) and the attention it has garnered in research circles. A notable achievement in the area was Deep Learning (DL) application in computer vision with outstanding daily life applications such as face-recognition, object detection, and more. However, robotics in general still depend on human inputs in certain areas such as localization, navigation, etc. In this paper, we propose a study case of robot navigation based on deep reinforcement technology. We look into the benefits of switching from traditional ROS-based navigation algorithms towards machine learning approaches and methods. We describe the state-of-the-art technology by introducing the concepts of Reinforcement Learning (RL), Deep Learning (DL) and DRL before before focusing on visual navigation based on DRL. The case study preludes further real life deployment in which mobile navigational agent learns to navigate unbeknownst areas.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.8
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• pp.19-26
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• 1995

In this paper, a fuzzy-neural hybrid control approach is proposed for controlling a mobile robot that can avoid an unexpected obstacle in a navigational space. First, to describe the global structure of a known environment, a heuristic collision-free space band is introduced. Based on the band, the moving information in the known environment is trained to a neural controller. Then, during the execution of a mobile robot navigation moving information at each position is given the neural controller. If the mobile robot encounters an unexpected obstacle, a fuzzy controller activates to avoid the unexpected obstacle. Finally, some numerical examples are presented to demonstrate the control algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.376-379
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• 2011

본 연구에서는 사용자 검색로그를 분석하여 사용자의 검색 목적에 따라 분류하고 그 안에 내제되어 있는 사용자의 검색 의도를 찾고자 하였다. 분석은 질의어 110개에 대한 검색로그를 기반으로 검색 목적에 따라 Navigational, Informational, Transactional로 분류하였다. 또한, 질의어를 카테고리별로 분류하였으며 각 결과를 가지고 사용자 검색 의도가 내제되었는지에 대하여 분석하였다. 분석 결과 각 질의어에 따른 검색 목적에 따라서 분포는 다르지만 검색 목적에 따른 검색 의도가 3가지 모두 내제되어 있음을 알 수 있었다. 또한, Informational의 경우에는 질의어에 대한 서로 다른 정보가 나타났으며, 질의어 안에서 사용자의 검색 의도가 나타남을 확인할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.259-261
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• 2015

In order to provide a safe and secure electronic navigational chart information services, AIS information, information on aids to navigation, maritime safety information, weather information, information on a variety of birds such as the data fused S-100 standards-based e-Navigation system should be established. S-101 ENC implement Rendering Engine analyzes the Drawing Instruction set generated by Portrayal Engine of the S-100 General Portrayal Model for is a job to be followed to establish the e-Navigation System to implement the S-101 ENC Should be. In this paper, we analyze the Drawing Instruction of the existing S-57 ENC and S-101 ENC is the basis for the implementation of the S-101 ENC.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.111-119
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• 2003

In order to improve navigational safety of ships, an ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface wind first and then carried out ocean wave hindercasting simulations according to the routes the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed iou pressure system Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, wave period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.3
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• pp.219-225
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• 2008

Since July 2006, marine traffic safety management system have been enforced to support the vessels transiting across the coastal area and the vessels coming in and out of ports in southwestern coastal area where heavy traffic density and marine casualties occurred frequently. The marine traffic volume for the marine traffic environmental assessment was measured by the information from RADAR and AIS system in the area. The distributions of marine casualties were analyzed in the main routes and traffic separation schemes during the last five years and the navigational dangerous elements were investigated with the influence of natural environment, the distribution of fisheries and survey questionnaire. Marine accidents of merchant ships have a tendency to decrease gradually but in case of fishing boats, the rate of marine accidents have a contrary results in this area during the last five years. The dangerous elements on navigation appeared to be the dense force from June to August, fisheries activities and the vessels which not follow the compulsory watch on VHF-band radio communication equipments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.147-156
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• 2003

In order to improve navigational safety of ships, on ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface winds first and then carried out ocean wave hindercasting simulations according to the routes of the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed low pressure system in Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, was period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.