• Journal of the Korea Society for Simulation
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• 제19권3호
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• pp.127-135
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• 2010

Modern marine navigation requires officers on the bridge to monitor a torrent of data on both the insides and outsides of the ship from numerous useful devices. But despite these tools, navigators can still find it difficult to make a safe decision for two reasons: one is that too much data if provided too quickly tends to cause fatigue and overwhelm the officer, and the other is that any inconsistency across data from several different types of devices can lead to confusion. Indeed, the fact remains that the many marine accidents can be attributed to human error, and hence there is a strong need for decision-support tools for marine navigation. One technique of providing decision support is through the use of simulation to evaluate or predict system dynamics over time using an accurate model. This paper, as a simulation method for risk prediction for a navigation safety information system of ship, suggests a navigation prediction simulation system using various knowledge bases and discrete event simulation methodology, and supports the validity of the system through the examples of components in a restricted navigation situation scenario.

• Journal of the Korean Institute of Intelligent Systems
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• 제20권2호
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• pp.226-233
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• 2010

The study of information fusion technology, which merges various types of data to recognize a situation more exactly, has begun in the area of national defense. Recently, the concept of information fusion is getting applied to other fields, and we are interested in maritime safety. In navigation, officers receive data about inside and outside of ship from several devices in bridge, and use it to recognize and predict the safety situation. However, too much and fast updated data might even fatigue mates, and there is the problem of inconsistency among data from several types of devices. This paper introduce how can use information fusion technology for the situation awareness and prediction of navigation safety, and show the realization possibility of Intelligent Navigation Safety Information System through an information fusion example in a specific situation scenario.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.53-54
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• 2015

The maritime industry is expanding at an alarming rate and as such there is a perpetual need to improve situation awareness in the maritime environment using new and emerging technology. Tracking is one of the numerous ways of enhancing situation awareness by providing information that may be useful to the operator. The tracking system described herein comprises determining existing states of own ship, state prediction and state compensation caused by random noise. The purpose of this paper is to analyze the process of tracking and develop a tracking algorithm by using ${\alpha}-{\beta}-{\gamma}$ tracking filter under a random noise or irregular motion for use in a warship. The algorithm involves initializing the input parameters of position, velocity and course. The actual positions are then computed for each time interval. In addition, a weighted difference of the observed and predicted position at the nth observation is added to the predicted position to obtain the smoothed position. This estimation is subsequently employed to determine the predicted position at (n+1). The smoothed values, predicted values and the observed values are used to compute the twice distance root mean square (2drms) error as a measure of accuracy of the tracking module.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.199-201
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• 2016

The performance of navigational equipments is advanced, but the importance of the practical capability of bridge device by ship's officer, ie the ability of risk prediction and the obligation of avoidance for reducing sea accident, has been constantly augmenting. This abilities and obligation may be represented in the cognitive competence of navigational officer. Different levels of ship's bridge team was carried out rescue maneuvering by ship handling simulator and then it analyzed the resulting of initial response in cognitive progress by case based on trajectory. Further, the data will be used as training and evaluation model of cognitive situation.

• Journal of Navigation and Port Research
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• 제40권2호
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• pp.83-87
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• 2016

The maritime industry is expanding at an alarming rate hence there is a perpetual need to improve situation awareness in the maritime environment using new and emerging technology. Tracking is one of the numerous ways of enhancing situation awareness by providing information that may be useful to the operator. The tracking module designed herein comprises determining existing states of high dynamic target warship, state prediction and state compensation due to random noise. This is achieved by first analyzing the process of tracking followed by design of a tracking algorithm that uses ${\alpha}-{\beta}-{\gamma}$ tracking filter under a random noise. The algorithm involves initializing the state parameters which include position, velocity, acceleration and the course. This is then followed by state prediction at each time interval. A weighted difference of the observed and predicted state values at the $n^{th}$ observation is added to the predicted state to obtain the smoothed (filtered) state. This estimation is subsequently employed to determine the predicted state in the next radar scan. The filtering coefficients ${\alpha}$, ${\beta}$ and ${\gamma}$ are determined from a pre-determined value of the damping parameter, ${\xi}$. The smoothed, predicted and the observed positions are used to compute the twice distance root mean square (2drms) error as a measure of the ability of the tracking module to manage the noise to acceptable levels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.395-400
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• 2006

Among the various error sources in positioning and navigation, the paper focuses on the modeling and prediction of receiver clock bias and then tries to achieve positioning based on simulated and predicted clock bias. With the SA off, it is possible to model receiver clock bias more accurately. We selected several types of GNSS receivers for test using ARMA model. To facilitate prediction with short and limited sample pseudorange observations, AR and ARMA are compared, and the improved AR model is presented to model and predict receiver clock bias based on previous solutions. Our work extends to clock bias prediction and positioning based on predicted clock bias using only 3 satellites that is usually the case under urban canyon situation. In contrast to previous experiences, we find that a receiver clock bias can be well modeled using adopted ARMA model. Test has been done on various types of GNSS receivers to show the validation of developed model. To further develop this work, we compare solution conditions in terms of DOP values when point positioning is conducted using 3 satellites to simulate urban positioning environment. When condition allows, height component is derived from other ways and can be set as known values. Given this condition, location is possible using less than 2 GNSS satellites with fixed height. Solution condition is also discussed for this background using mode of constrained positioning. We finally suggest an effective predictive time span based on our test exploration under varied conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.66-72
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• 2003

The paper describes on the implementation of three-dimensional visualization system that is to visualize meaning of the statistical prediction results of marine casualty with easy of understanding. Graphical User Interface(GUI) and Web based Virtual Reality (VR) technology are mainly introduced in the system development. In addition, the time based prediction models of the marine casualty and the risk level are developed to display daily situation. As operating test results of the system, it is known that complicated statistical results can be shown as simple colour in the three-dimensional virtual space.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.509-523
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• 2005

We are developing a novel framework, PRIDE (PRediction In Dynamic Environments), to perform moving object prediction (MOP) for autonomous ground vehicles. The underlying concept is based upon a multi-resolutional, hierarchical approach which incorporates multiple prediction algorithms into a single, unifying framework. The lower levels of the framework utilize estimation-theoretic short-term predictions while the upper levels utilize a probabilistic prediction approach based on situation recognition with an underlying cost model. The estimation-theoretic short-term prediction is via an extended Kalman filter-based algorithm using sensor data to predict the future location of moving objects with an associated confidence measure. The proposed estimation-theoretic approach does not incorporate a priori knowledge such as road networks and traffic signage and assumes uninfluenced constant trajectory and is thus suited for short-term prediction in both on-road and off-road driving. In this article, we analyze the complementary role played by vehicle kinematic models in such short-term prediction of moving objects. In particular, the importance of vehicle process models and their effect on predicting the positions and orientations of moving objects for autonomous ground vehicle navigation are examined. We present results using field data obtained from different autonomous ground vehicles operating in outdoor environments.

• Journal of Advanced Navigation Technology
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• 제13권5호
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• pp.699-704
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• 2009

The requirements of disaster prevention have been constantly increasing on highly disaster frequency by Global warming and environmental destruction. The damage occur more highly, especially when it's on the localized change of weather. It requires that we have methods of disaster prevention locally. In this paper, we design and implement a breakwater disaster prevention system integrated wireless sensor technique for the shore breakwater of East Sea that is raised anxiety about an accident occurrence due to stormy weather. The provided disaster prevention system perceive the seriousness of the situation that is chance of that happening by the information of realtime remote situation and a prediction system so that it could be of some help to reduce the damage of disaster and the cost of recovery.

• Journal of Navigation and Port Research
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• 제39권3호
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• pp.199-207
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• 2015

In ports of Korea, the marine traffic flow is congested due to a large number of vessels coming in and going out. In order to improve the safety and efficiency of these vessels, South Korea is operating with a Vessel Traffic Service System, which is monitoring its waters for 24 hours. However despite these efforts of the VTS (Vessel Traffic Service) officers, collisions are occurring continuously, the risk situation is analyzed that occurs once in about 20 minutes, the risk may be greater. It investigated to reduce these accidents by providing a safety standard for collision danger in a timely manner. Thus, this study has developed a risk prediction module to predict risk in advance. This module can avoid collision risk to adjust the speed and course of ship using a risk evaluation model based on ship operator's risk perspective. Using this module, the ship operators and VTS officers can easily be identified risks in complex traffic situations, so they can take an appropriate action against danger in near future including course and speed change. To verify the effectiveness of this module, this paper predicted the risk of each encounter situation and confirmed to be capable of identifying a risk changes in specific course and speed changes at Busan coastal water.