• Journal for History of Mathematics
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• v.28 no.5
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• pp.249-262
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• 2015

Simon Stevin, a mathematician active in the Netherlands in early seventeenth century, parlayed his mathematical talents into improving navigation skills. In 1605, he introduced a technique of calculating the distance of loxodrome employed in long-distance voyages in his book, Navigation. He explained how to calculate distance by 8 different angles, and even depicted how to make a copper loxodrome model for navigators. Particularly, Stevin clarified in the 7th copper loxodrome model on the unique features of equiangular spiral curve that keeps spinning and gradually accesses from the vicinity to the center. These findings predate those of Descartes on equiangular spiral curve by more than 30 years. Navigation, a branch of actual mathematics devised for the survival of sailors on the bosom of the ocean, was also the first step to the discovery of new mathematical object.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.491-494
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• 2006

Kalman filtering (KF) is hard to be applied to the SINS (Strap-down Inertial Navigation System)/RDSS (Radio Determination Satellite Service) integrated navigation system directly because the time delay of RDSS positioning in active mode is random. BP (Back-Propagation) Neuron computing as a powerful technology of Artificial Neural Network (ANN), is appropriate to solve nonlinear problems such as the random time delay of RDSS without prior knowledge about the mathematical process involved. The new algorithm betakes a BP neural network (BPNN) and velocity feedback to aid KF in order to overcome the time delay of RDSS positioning. Once the BP neural network was trained and converged, the new approach will work well for SINS/RDSS integrated navigation. Dynamic vehicle experiments were performed to evaluate the performance of the system. The experiment results demonstrate that the horizontal positioning accuracy of the new approach is 40.62 m (1 ${\sigma}$), which is better than velocity-feedback-based KF. The experimental results also show that the horizontal positioning error of the navigation system is almost linear to the positioning interval of RDSS within 5 minutes. The approach and its anti-jamming analysis will be helpful to the applications of SINS/RDSS integrated systems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.902-909
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• 2015

In this paper, monovision based relative navigation for a satellite proximity operation is studied. The chaser satellite only uses one camera sensor to observe the target satellite and conducts image tracking to obtain the target pose information. However, by using only mono-vision, it is hard to get the depth information which is related to the relative distance to the target. In order to resolve the well-known difficulty in computing the depth information with the use of a single camera, the active contour method is adopted for the image tracking process. The active contour method provides the size of target image, which can be utilized to indirectly calculate the relative distance between the chaser and the target. 3D virtual reality is used in order to model the space environment where two satellites make relative motion and produce the virtual camera images. The unscented Kalman filter is used for the chaser satellite to estimate the relative position of the target in the process of glideslope approaching. Closed-loop simulations are conducted to analyze the performance of the relative navigation with the active contour method.

• Journal of Navigation and Port Research
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• v.44 no.5
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• pp.423-429
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• 2020

A ship's automatic steering system is the basis for addressing control difficulties related to course-changing and course-keeping during navigation through heading angle control, and is a link in realizing unmanned and autonomous ships. This study proposes a robust RCGA-based linear active disturbance rejection controller (LADRC) design method considering environmental disturbances, measurement noise, and model uncertainties in designing a ship heading controller for use when the ship is sailing. The LADRC consisted of a transient profile, a linear extended state observer, and a PD controller. The control gains in the LADRC with the linear extended state observer were adjusted by RCGAs to minimize the integral of the time-weighted absolute error (ITAE), which is an evaluation function of the control system. The proposed method was applied to ship heading control, and its effectiveness was validated by comparing the propulsive energy loss between the proposed method and a conventional linear PD controller. The simulation results showed that the proposed method had the advantages of lower propulsive energy loss, more robustness, and higher tracking precision than the conventional linear PD controller.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.916-919
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• 1996

An real-time active beacon localization system for mobile robots is developed and implemented. This system permits the estimation of robot positions when detecting light sources by PSD(Position Sensitive Detector) sensor which are placed sparsely over the robot's work space as beacons(or landmarks). An LSE(Least Square Estimation) method is introduced to calibrate the internal parameters of a model for the beacon and robot position. The proposed system has two operational modes of position estimation. One is the initial position calculation by the detection of two or more light sources positions of which are known. The other is the continuous position compensation that calculates the position and heading of the robot using the IEKF(Iterated Extended Kalman Filter) applied to the beacon and dead-reckoning data. Practical experiments show that the estimated position obtained by this system is precise enough to be useful for the navigation of robots.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.387-392
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• 2006

There have been several problems in treating shipboard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on. It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.315-320
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• 2006

There have been several problems in treating shipboard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on. It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.3
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• pp.376-382
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• 2010

These days, a study on 'Unmanned Surface Vehicle (USV)' has made very active progress in many countries. Even if it is being expected that there will be a great demand of USV for wide field, such as military operation, private sector, and etc., the study of USV in Korea is still at an early stage. For this reason, we have made a very small USV which is composed of dual mode (autonomous and remote control). The TCP/IP communication is applied to the USV.

• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.147-155
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• 2000

In this paper, we propose the Chaos Fuzzy controller to analyze the chaotic character of time series obtained from the specific plant and to predict the short-term for power consumption of the plant using the Fuzzy controller. We compared the predicted data with the active ones and checked the error generated by them after we time series of supplied power to the proposed controller. As a result of the simulation, we obtained a admirable consequence that the proposed controller can be advanced through various and accurate data acquisition, and continuous analysis of the resident and industrial environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.144-145
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• 2010

VTM is regarded as a core element in e-Navigation under developing by IMO. IMO's e-Navigation aims for VTM which could provide more navigational information for ships and provide more active VTS services for safe and efficient marine traffic environment. To be successful for VTM under e-Navigation, VTS operator's experience and ability for carrying out VTM tasks are essential. In this study, Decision-making support system for VTS operators are designed conceptually which support VTS operators' VTM tasks by providing informations on traffic risk, and predicted behaviour of ships. This paper describes a designed system with design concept, main functions, main elements and necessary technologies to be developed.