• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.139-143
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• 2004

Lee et al have proposed a framework for the linguistic map-based navigational planning of a mobile robot on dynamic environment and provided simulation results applied it to the static environment[1], In this paper, we extends the navigational planning of a mobile robot into dynamic environment. There are two kinds of dynamic obstacles： (1) Time-obstacles that change condition of obstacles with time. (2) Space-obstacles that move their position with time. We propose an algorithm which a mobile robot identifies and avoids the two kinds of dynamic obstacles. The proposed algorithm consists of two stages： (1) The fuzzy logic-based perception stage which identifies the dynamic obstacles around a mobile robot by using sensory data and fuzzy rules, (2) The planning stage which plans the path to goal by avoiding the dynamic obstacles[2-6]. We provide computer simulation results for a mobile robot in order to show the validity of the proposed algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.396-401
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• 2004

Recently a framework for the cognition-based navigational planning of a mobile robot on dynamic environment has been proposed, and simulation results applied it to the static environment been presented [1]. In this paper, we propose a linguistic map-based framework for the navigational planning of mobile robots, which is applicable to the dynamic environment including not only static obstacles but also dynamic obstacles such as temporal-spatio obstacles, by extending Lee et al. 's framework, and provide computer simulation results obtained by applying to a mobile robot on the dynamic environment in order to show the validity of the proposed algorithm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.305-310
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• 2016

This study identified necessary navigational support services to prevent accidents through an examination and a survey on the navigation and communication systems of non-SOLAS ships. The functional and operational requirements for the identified navigational support services were discussed accordingly. Among the navigational support services proposed are an Electronic Navigational Chart (ENC) service, a route planning service, an operation monitoring service, and collision prevention support services for ships in coastal areas. To facilitate the identified navigational support services, ship navigation system, shore supporting centre and maritime communication network were discussed as a digital infrastructure. The operational methode for the digital infrastructure were discussed in the service scenarios for ships carrying dangerous cargo, large ships over 200 meters in length and high speed passenger ships over 15 knots in speed. This study will facilitate the development of policies for the improvement of ship operation management in Korean coastal waters and will contribute to improving the navigational safety of non-SOLAS ships.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.2
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• pp.171-177
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• 2004

In this paper, we propose a cognition-based navigational algorithm for mobile robots in dynamic environments. The proposed algorithm consists of two main stages: (i) the fuzzy logic-based perception stage that constructs knowledge from the sensory data for subsequent usage in reasoning, and (ii) the planning stage that identifies the path between a starting and a goal position within its environment on the basis of the knowledge base on the environment and information from the perception stage. A mobile robot reasons places and moves to goal using ambiguous information and ambiguous knowledge through ‘perception’ and ‘planning’. We provide computer simulation results for a mobile robot in order to show the validity of the proposed algorithm.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.323-335
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• 2016

The main reason of marine casualties is the human error in respect of ship's operation. The human error of officers in charge of a navigational watch is related to their abilities to handle of navigational equipment. Navigational devices play a key role to help officers decide what to do for safe navigation. Thus, the abilities to handle of navigational equipment mean not only operation of devices but also entire understanding of the system such as interpretation of information obtained from devices, appropriate use of information considering navigational circumstance. Qualification of seafarers is in accordance with STCW and detailed training courses for their qualification are provided by IMO model course series. Recently, ships engaged on international voyages shall be fitted with an ECDIS not later than the first survey on or after 1 July 2018. As increasing use of ECDIS on ships, marine casualties related to ECDIS are on the rise. The primary causes of the accidents are lacking understanding of ECDIS system, wrong presentation of information on display, wrong safety setting by seafarers who use ECDIS, using small-scale chart and missing charts update. As a result of these primary causes, some problems like wrong route planning and use of limited or omitted information occur. It could be happening by inappropriate seafarers' training which is not sufficient to support improving abilities of officers to handle navigational equipment. For efficient training, it is need to develop training courses. Applying full mission simulation system to seafarers' training courses with case studies and best practices which are well-constructed scenarios based on true marine casualties can increase the effect of training. To use the simulation system, it is possible that seafarers are trained under condition that closely resemble real situation. It should be considered that IMO model course be revised depending on the level of seafarers also. It could be helpful for increasing seafarers' abilities of equipment operation in place of accumulation of experience spending much time. In the short term, effort of training courses improvement for seafarers is needed and long term, it should be tried to provide stable system and services relate to ECDIS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.1 no.1
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• pp.9-25
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• 1995

Although the studies carried out in recent years have provied much new information about channel widths and alignment, they are not consistent in their results. In addition, as a result of variations in local condition and type of traffic accommodated, the dimensions of the channel widths vary over a wide range. Therefore, the recommendation made by the maritime engineering organizations over the world, do not offer detailed and decisive optimal design criteria and are all different. It, therefore, was attempted in this paper to draw a decisive guideline on the optimal widths and alignment of the navigational channels, which can be utilized by the port designers at the stage of the planning. The guideline was drawn through the comparison and analysis of the existing guidelines of the U.S.A, Japan and PIANC and simulation experiment. The simulation experiment was carried out using the "Off Line Port and Waterway Design Simulator" to find the optimal dimensions of the widths of the navigational channels. 90 different simulation runs were conducted at the 3 different secenario channels. New guidelines, the result of the study, is expected to be used usefully by the Korean port designers when designing the rapodly developing ports in Korea. in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.782-791
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• 2005

In this paper, path planning and tracking problems are mentioned to guarantee efficient and safe navigation of autonomous mobile robots. We focus on the path planning and also deal with the path tracking and obstacle avoidance. We improved the conventional distance transform (DT) algorithm for the path planning. Using the improved DT algorithm, we obtain paths with shorter distances compared to the conventional DT algorithm. In the stage of the Path tracking, we employ the fuzzy logic controller to conduct the path tracking behavior and obstacle avoidance behavior. Through computer simulation studies, we show the effectiveness of the Nosed navigational algorithm for autonomous mobile robots.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.295-299
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• 2005

In this paper, path planning and tracking problems are mentioned to guarantee efficient and safe navigation of autonomous mobile robots. We focus on the path planning and also deal with the path tracking and obstacle avoidance. We improved the conventional distance transform (DT) algorithm for the path planning. Using the improved DT algorithm, we obtain paths with shorter distances compared to the conventional DT algorithm. In the stage of the path tracking, we employ the fuzzy logic controller to conduct the path tracking behavior and obstacle avoidance behavior. Through computer simulation studies, we show the effectiveness of the proposed navigational algorithm for autonomous mobile robots.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.737-740
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• 2001

We develope the PC based SPS to improve safety at sea, save fuel and time during a voyage and makes mariner's work more efficient and comfortable in ship navigation, who propose the auto-navigation system with SPS as basic main system. Developed SPS operate the function to monitor navigational equipment and to substitute a broken main navigational equipment such as CIS, ECDIS, or Radar/ARPA, automatically. These can be improve more efficient and comfortable ship navigation and reduce these traffic accident. The SPS has the function as DB and network server, additionally.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.45-54
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• 1992

It become increasingly important to design user interface to carry low complexity. The cognitive limitations of users severely restrict utility of highly intelligent but complex modern systems. Since humans are known to use schemas to reduce cognitive complexity, imposing good consistency to an interface design that may help that user form useful schemas will provide powerful control over the complexity. This present a research effort to develop a quantitative method for evaluating interface complexity that the user would experience planning his or her course of action. Taking into account the user's potential schemas, a quantitative measure based on information theory was develped to assess the navigational complexity. This approach does not rely on the subjective judgment of the researcher as most schemes dealing with user schemas do. The proposed method may benefit the rapid prototyping approach to design a better user interface by allowing handy assessment of the design.