• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.114-129
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• 1996

This paper describes the whole development phase for the underwater vehicle actuating system with high hydroload torque disturbance. This includes requirement analysis, system modeling, control algorithm design, real time implementation, test and performance evaluations. As for driving control algorithms, fuzzy logic, variable structure and PD(Proportional-Differential) algorithm were designed and implemented on board controller using a single chip microprocessor. Intel 8797. And test and performance evaluation is carried out both single test and wystem integration test. We could confirm the basic performance of actuating system through the single test and gereral developing work of any actuating systems was finished with a single performance test of actuating system without system integration test. But, we suggested that system integration test be needed. System integration test is carried out using G/C HILS(Guidance and Control Hardware-In-the -Loop Simulation) which is constituted flight motion simulator, load simulator, real time host computer and the related subsystems such as inertial navigation system, power supply system and Guidance and Control Computer etc.. The most important practical contribution of this paper is that full system characteristics such as minimal control effort, enhancement of guidance and autopilot performance by the actuating system using G/C HILS technique are investigated. Through full running G/C HILS, in spite of the passing to single tests, some control algorithm resulted in failure as to stability of full system and system time frame.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.4
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• pp.187-194
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• 2016

When performing experiments in indoor and outdoor environment, we need a system that monitors a volunteer to prevent dangerous situations and efficiently manages the data in real time. We developed a guidance device for visually impaired person that guides the user to walk safely to the destination in the previous study. We set a POI (Point of Interest) of a specific location indoors and outdoors and tracks the user's position and navigate the walking path using artificial markers and ZigBee modules as landmark. In addition, we develop path finding algorithm to be used for navigation in the guidance device. In the test bed, the volunteers are exposed to dangerous situations and can be an accident due to malfunction of the device since they are visually impaired person or normal person wearing a eye patch. Therefore the device requires a system that remotely monitors the volunteer wearing guidance device and manages indoor or outdoor a lot of map data. In this paper, we introduce a managing system that monitors the volunteers remotely and handles map data efficiently. We implement a management system which can monitor the volunteer in order to prevent a hazardous situation and effectively manage large amounts of data. In addition, we verified the effectiveness of the proposed system through various experiments.

• Spatial Information Research
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• v.20 no.3
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• pp.83-93
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• 2012

Recent environmental concerns have made interest in environment-friendly transportation means such as walking, biking, and public transportation. However, since it is difficult to move long distance by walking or biking, their scope of application is rather limited. On the other hand, public transportation can solve traffic congestion, a recent social issue, though its usability may depend on its time schedule. Currently available information services on public transportation in the Web do not reflect well such traits of the public transportation; thus, in some cases, they may provide wrong information to end users. To solve such problems and provide information based on timetable of public transportations, this paper proposes a STP(Space Time Point) data model. Unlike existing space-time data models, this model recognizes the bottommost element of an object as a point and structures these points in hierarchical way to define an object. In particular, It can make it possible to implement a variety of dynamic spatial objects changing object information according to time. An objective of this study is to design a STP model for bus and subway based on timetables of public transportation in Daejeon area and builds a system to provide path navigation. With the designed navigation function, a path from the Daejeon National Cemetery to Hannam University was searched by time slot. The result showed that the system provided different paths by time, as the system guided different paths when bus operation was limited in midnight. As existing data model could not provide such results, it is confirmed that the system can provide path navigation based on real-time traffic information. It is expected that based on such functionality, it is possible to provide additional functionalities by applying diverse data models such as real-time transport information or traffic history information.

• Journal of the Korean Institute of Navigation
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• v.17 no.3
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• pp.1-14
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• 1993

The master of ship is always authorised to perform whatever acts are ordinarily necessary for the safe and proper prosecution of the voayge with regard to both ship and cargo. In other words, when a ship is away from her home port, where her business was managed, the master generally carried the owner's authority, and ordinarily he had power to enter into engagements, on their behalf, for carrying goods in the ship, or for letting her service, provided those engagements were consistent with the usual manner of employing her adopted by the owners. Accordingly he has always to decide onboard for an adequate applying of statutory law and cases whenever he acts. But the master would appear to have no such autho-rity where he can communicate with the owners without difficulty as, now-a-days, he nearly always can. This paper, therefore, intend to review some guidance of his authority in accordance with the Korean Code of Commerce as well as precedent based on it. The paper is also simply to place at the disposal of young shipmasters and those who aspire to command some legal information concerning limit of master's authority away from vessel's home port through legal commentation on the precedent, which may assist them to a better understanding of the many problems they may be faced with in the course of their ca-reers. In order to make an efficient study of legal structure concerned for shipmaster's authority, several up-to-date precedents are selected and described herein by writer's opinion for preventing unreasonable legal dispute in this field before courts in future.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.9
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• pp.759-765
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• 2016

This paper presents the principle, dynamics modeling and control, hardware implementation, and flight test result of a hybrid-type unmanned aerial vehicle (UAV). The proposed UAV was designed to provide both hovering and fixed-wing type aerodynamic flight modes. The UAV's flight mode transition was achieved through the attitude transformation in pitch axis, which avoids a complex rotor tilt mechanism from a structural and control viewpoint. To achieve this, a different navigation coordinate was introduced that avoids the gimbal lock in pitch singularity point. Attitude and guidance control algorithms were developed for the flight control system. For flight test purposes, a quadrotor attached with a tailless fixed-wing structure was manufactured. An onboard flight control computer was designed to realize the navigation and control algorithms and the UAV's performance was verified through the outdoor flight tests.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.383-385
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• 2012

Confined Disposal Facilities(CDF) are an effective and commonly used management option for contaminated dredged material. CDF is an engineered contstruction for containment of contaminated dredged material to control potential releases to the environment. Although the concept is simple, constructing a CDF is a complex and non-standard process. In the process of planning a CDF, many different fields of expertise have to be considered, such as civil engineering, landscaping, chemistry, legislation, social impact, and environmental engineering. This paper provides the concise overview of common guidance on CDF.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.1949-1954
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• 2010

The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region(dead band) due to the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference, and an angular increment is not detected. This problem can be overcome by mechanically dithering the gyroscope. This paper presents the design method of mechanical dither by the theoretical considerations and the verification of the theoretical equations through FEM(Finite Element Method) applications. As a result, the maximum prediction error of resonant frequency and peak dither rate was under 5 percent. The theoretical equations for the mechanical performances of dither can be said to be feasible.

• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.698-704
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• 2018

When the new ammunition is designed, it is necessary to confirm in advance how long the target distance is depends on the shape and weight of the designed ammunition. Therefore we can use commercial software such as PRODAS to predict the target distance in the design stage. This commercial software has aerodynamic data for various ammunition shape and calculates the target range by calculating the kinetic equations of the ammunition using the aerodynamic data most similar to the designed ammunition. The ammunition for predicting the target distance through software such as PRODAS is a non-guided ammunition that has no control after launch but the glide type ammunition is guided and control ammunition. So it is predicts the state of ammunition after the launch. A new type of simulator is needed to analyze the maximum range and to verify the onboard guided and control algorithm. The simulator constructed in this paper is an optimized simulator for glide type ammunition. Unlike unmanned aircraft and guided missiles. The rotation characteristics of the ammunition are considered and the navigation initialization algorithm is applied. The constructed simulator confirmed the performance by performing maximum range analysis of glide type ammunition.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.5
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• pp.966-978
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• 2014

Currently, majority small ship's clutch for power transmission to propeller relies on multi plate hydraulic clutch regardless its size. Most of the small ships do not have a spare equipments of clutch. Furthermore, many ship engineers do not have an ability as well as enough experience to solve this problem related to the hydraulic clutch during the voyage. Therefore, any small problems cause many serious marine accidents. Once the clutch has problem, almost of all ships can not sail by itself anymore and it must be towed by salvage boat, maritime police ships, or fish guidance boat etc. In this case, all the accidents will be categorized as a marine accident and they all need to go through marine accident court inquiries. In this study, an understanding of each crew on hydraulic clutch system has been profoundly measured. Furthermore, the knowledge on an emergency navigation protocol of each crew has been also profoundly checked. Additionally, various surveys on hydraulic clutch classes has been performed and its satisfaction of crews on this topic have been carefully checked based on various feedback from students who took these courses. All of the above data from this study will be used to reduce marine accidents in current marine industry.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.1
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• pp.74-79
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• 2013

Early remotely-piloted aircraft system (RPAS) development focused on simple reconnaissance to obtain information by visual observation for military demands. Currently, various types of remotely-piloted aircraft (RPA) is being developed worldwide for applications in many different areas. As RPA avionics are combined with CNS/ATM technologies, RPA capabilities will be enhanced and the market is expected to grow rapidly. ICAO has been held the Air Navigation Commission on 14 October 2011 to discuss revising Procedures for air navigation services (PANS) and guidance material related to RPA and their associated systems. It progressed that Annex 2 and 7 will be revised and came into effect from 2012. However most of incorporate revisions are not clear yet. Because the revision articles recommend follow requirements of the state(s). Considering operations of RPA in controlled airspace and between adjacent states, the qualification and training of RPA pilot will be one of the main issues for RPA operation. In this paper, we will take a look at international and domestic trends of regulation framework in ICAO and RPA advanced country in chapter 2.1 and suggest about consideration of remote pilot qualification and training for establishing regulations of remote pilot license.