• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.809-818
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• 2019

Since January 1, 2020, the International Maritime Organization (IMO) has put in place strong regulations to reduce air pollution caused by ships by lowing the upper limit of ship fuel oil sulfur content from 3.5% to 0.5% for ships passing through all sea areas around the world. Although it is important to reduce air pollutants by using fuel oil with low sulfur content, reducing the amount of energy waste through the economic operation of a ship can also help reduce air pollutants. Ships can follow designated routes accurately even under the influence of noise using autopilot systems. However, regardless of their quality, the performance of these systems is af ected by noise; heading angles with added measurement noise from the gyroscope are input into the autopilot system and degrade its performance. A technique to solve these problems reduces noise effects through the application of a Kalman filter, which is widely used in condition estimation. This method, however, cannot completely eliminate the effects of noise. Therefore, to further improve noise removal performances, in this study we propose a better denoising method than the Kalman filter technique by applying a multi-layer perceptron (MLP) in forward direction motion and a Kalman Filter in rotation motion. Simulations show that the proposed method improves forward direction motion by preventing the malfunction of a rudder more so than merely using a Kalman Filter.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.437-442
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• 2009

The PID controller type autopilot is applied to support shipmaneuvering for course-keeping and heading control. A control constants of autopilot system should be evaluated by promoting energy loss (fuel consumption) from the view point of economic efficiency of the ship. This paper is obtained control constants of autopilot system from the RCGA pursued the minimum energy loss. In addition, the controller which is designed involves a constrained optimization problem. The performance of the proposed method is demonstrated through a set of simulation.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.27-37
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• 1995

A performance index is very important and indispensable to the evaluation of automatic steering system of ships in open sea from the viewpoint of energy saving. In this paper, we derive the performance index of automatic steering system from the concept of energy loss of propulsive power. The index is found to consist of three terms, energy loss due to elongation of sailing distance, energy loss due to steering, and energy loss due to yawing motion. We also provide two kinds of calculation method on the performance index ; frequency response analysis and digital simulation. The numerical calculations are carried out for an ore carrier and a fishing boat by both methods. The frequency response analysis is found to be useful if the system is linear and the disturbance on ship is not large. If the system is nonlinear or the disturbance is excessive, the method of digital simulation has to be applied for the accurate evaluation of the performance index. Further investigations into the effects of nonlinear elements such as weather adjuster, power unit etc. on the performance index, will be dealt with in another paper.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.41-50
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• 2018

In our society, recently, the concept of social economy stands out as an alternative to the mainstream economy in the market. It is noteworthy that although the social economy has the nature of practical field of civil society, the government has a willingness to actively support the social economy as a means of getting visible result of job creation. The social economy in Korea is being fostered by the government and understood within the framework of a very limited policy goal of providing jobs for the vulnerable. The problem is that the social value and community implications of the social economy are disappearing while the social economic organizations have higher policy status and become more and more dependent on the government's financial support. This paper suggests that the discourse on the social economy should be reconstructed while holding the problem of this situation.

• Korean Security Journal
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• no.48
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• pp.235-258
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• 2016

The purpose of this study is to find out the effectiveness of the group guidance program using positive psychology for national security related university entrants' psychological wellbeing. This study is to investigate the influence of group guidance program on the increase of psychological well-being of university entrants through active and deliberate program based on the positive psychology. To achieve this purpose, thirty nine students (male 19, female 20) among national security related university entrants were selected and allocated to experimental and comparative groups. Experimental group was nineteen students (male 10, female 9), and comparative group was twenty students (male 9, female 11). Experimental group was divided into two teams (male and female team), and guided by each leader. The group guidance was participated in total ten-week sessions, fifty mins per week. The results were as follows; First, the group guidance program using positive psychology for national security related university entrants' had a positive effect on the students' psychological wellbeing. Second, effects of subordinate factors (autonomy, controling environment, personal growth, positive relations) in comparison in pre and post test of program had an influence very positive or positive, while one factor (purpose in life) didn't show a positive effect.

• Korean Security Journal
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• no.44
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• pp.139-167
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• 2015

It is known that Psychopathy is excessively selfish, using as a tool to achieve the purpose to others, irresponsible, easy liars in common. They were recognized that it is people of harmful to society, impulsive, attacking others body, ignorant others safety, enjoying or callousing others suffers. But, another aggressive behaviors are described as pro-social aggressive acts as the cops bring under control by firearms to hostage committing a crime in social norms. The proper aggression is related with national security and safety of the people that is pro-social aggression for nation and human society. Security service with the legal grounds and the convinced commitment needs self-giving works, self-sacrificial security-activity is in the center of security service. These days, psychologists reveal the people of psychopathy are CEO, politician, broadcaster, surgeon, special forces, police officer. And they distinguish themselves and contribute to a community in various fields. Therefor, this research wanted to find out the relationship between fearlessness, coldheartedness in the PPI-R(applying to the university student for checking psychopathy, except anti-social traits) and pro-social aggression, self-sacrificial security-activity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.557-565
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• 2021

Path-following control is considered as one of the most fundamental skills to realize autonomous navigation of marine vessels in the ocean. This study addresses with the path-following control for a ship in which there are environmental disturbances in the directions of the surge, sway, and yaw motions. The guiding principle and back-stepping method was utilized to solve the ship's tracking problem on the reference path generated by a virtual ship. For path-following control, error dynamics is one of the most important skills, and it extends to the research fields of automatic collision avoidance and automatic berthing control. The algorithms for the guiding principles and error variables have been verified by numerical simulation. As a result, most error variables converged to zero values with the controller except for the yaw angle error. One of the most interesting results is that the tracking errors of path-following control between two ships are smaller than the existing safe passing distances considering interaction forces from near passing ships. Moreover, a trade-off between tracking performance and the ship's safety should be considered for determining the proper control parameters to prevent the destructive failure of actuators such as propellers, fins, and rudders during the path-following of marine vessels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.209-215
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• 1979

The manoeuvrabilities of a ship are decided by the values of her manoeuvring indices. The manoeuvring indices consist of two kinds: indices K and T. The former decides a ship's turning ability and the latter, the length of time delay to a steady turning motion after her rudder has finished the turn of an ordered angle. In this paper, the author figured out the values of the manoeuvring indices of the m. s. 'SAEBADA' (GT: 2,275,7 ton), the training ship of tile National Fisheries University of Busan through her Z test and analyzed these values and the other data which were obtained from her Z test to study her manoeuvrabilities. The results of]tamed are summarized as follows: 1. The manoeuvring indices K' of the m. s. 'SAEBADA' were $1.052(at\;10{\circ}\;Z\;test)\;0.925(at\;20{\circ}\;Z\;test)\;and\;0.877(at\;30{\circ}\;Z\;test)$. Her manoeuvring indices $0.815(at\;10{\circ}\;Z\;test)\;0.502(at\;20{\circ}\;Z\;test)\;and\;0.441(at\;30{\circ}\;Z\;test)$. Her above calculated values K', T' showed that her obeying ability to the turn of her rudder was more increased when her rudder was used to large angle than to small angle, but on the other hand in this case her turning ability was slightly reduced. 2. As it appeared that the calculated K'-values of the m.s. 'SAEBADA' were slightly smaller than the standard K'-values of the fishing boats similar in length, and her overshoot angles at her Z test were greater than other general ships, her turning ability was found to t]e slightly lower. 3. When the m. s. 'SAEBADA' took a turn at her $10^{\circ}\;Z$ test, running distance was about 8.6 times her own length and didn't exceed the standard manoeuvrability distance, 5 to 11 times general ships' own length, therefore she was considered to have a good manoeuvrability synthetically.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.3-43
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• 2018

Auf die ganze Welt macht unbemannte $Flugger{\ddot{a}}te$(sog.Drohnen) in vielen Bereichen rasch Fortschritte und Anwendungen gezeigt. Nachdem ferngesteuerte Drohnen $urspr{\ddot{u}}nglich$ $prim{\ddot{a}}r$ $f{\ddot{u}}r$ $milit{\ddot{a}}rische$ Zwecke entwickelt wurden, $erh{\ddot{o}}cht$ sich derzeit ihre zivile Nutzung sowohl im Freizeit- als auch im Dienstleistungsbereich(Paketdrohnen, Drohnen-taxi) stetig. Mit der vermehrten Drohnennutzung steigen allerdings auch die damit verbundenen Risiken und Herausforderungen. In Zusammenhang damit stellt sich dann die Frage, ob $gegenw{\ddot{a}}rtige$ Vorschriften im Bereich von Luftrecht zurecht gekommen sind. Es sieht sich gerade der zwei Schwerpunkt $gegen{\ddot{u}}ber$. Erstens kann $Passagierebef{\ddot{o}}rderung$ mit unbemanntem Luftfahrzeug(mehr als 150kg) im $gegenw{\ddot{a}}ritigen$ Luftrecht keine Anwendung finden. Denn das kor. Luftsicherheitsgesetz und sein Durchsetzungsverordnung definieren die Terminologie von unbemannten Luftfahrzeugen und unbemannten $Flugger{\ddot{a}}te$ als "wenn eine Person nicht an Bord geht und ferngesteuert wird". Also soll Drohne nach dieser gesetzlichen Definition nur "ohne Person" geflogen werden. Das besagt ohne Piloten und ohne Passagiere. Zweitens ist unbemannte $Flugger{\ddot{a}}te$(weniger als 150kg) nicht auf Handelsgesetz anzuwenden, auf das ${\ddot{u}}ber$ Anspruchsgrundlage und Zurechnungsnorm des gewerblichen Luftverkehr geregelt ist. Der unbemannte Luftfahrzeuglieferdienst bringt nicht nur die Gefahr einer $Besch{\ddot{a}}digung$ des Frachtguts mit sich, sondern auch die Gefahr von $Bodensch{\ddot{a}}den$ durch Dritte. Gemäß ${\S}$ 896 des Handelsgesetzes ist aber die Anwendung von unbemannte $Flugger{\ddot{a}}te$(weniger als 150kg) $hierf{\ddot{u}}r$ begrenzt, weil unbemannt $Flugger{\ddot{a}}te$ $einschl{\ddot{a}}gig$ in Ultralight $Flugger{\ddot{a}}t$ ist, die im Handelsgesetz ausschließlich besteht. Technische Fortschritt und die dadurch $erm{\ddot{o}}glichten$ kommerziellen Anwendungen werden die Nachfrage nach unbemannter $Flugger{\ddot{a}}te$ wecken. Die Umsetzung der $bez{\ddot{u}}glichen$ Vorschriften sollte auch diese Entwicklung aktiv begleitet und $fr{\ddot{u}}hzeitig$ kommuniziert und erarbeitet werden, damit Hersteller und Nutzer $fr{\ddot{u}}hzeitig$ Planungssicherheit haben.