• Journal of the Society of Naval Architects of Korea
• /
• v.51 no.6
• /
• pp.548-555
• /
• 2014

As a considerable, experimental approach, an Auto-carriage type of $CO_2$ welding machine and a MIG(Metal Inert Gas) welding robot under inert gas atmosphere were utilized in order to realize Al 5083 welding applied to hull and relevant components of green Al leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, non-ferrous material, applied to manufacturing of co-environmental Al leisure ships. With respect to welding condition to minimize the thermal deformation, 150A and 16V at the wire-feed rate of 6mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(Heat Affected Zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5mm thickness, 284.62MPa of tensile strength and 11.41% of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification(WPS).

• Proceedings of the Korea Association of Information Systems Conference
• /
• 2001.12a
• /
• pp.348-361
• /
• 2001

최근 몇 년 사이에 인터넷(Internet) 공간상에서 거래되는 선박매매 사이트의 출현으로 인하여 사이버해운거래 시장이 형성되고 있다. 인터넷은 다양한 정보제공자에 의해 광범위한 분야의 정보를 멀티미디어 형태로 전달한다는 점에서 매우 각광을 받고 있지만 이용자의 증가로 무수한 정보들이 걸러지지 못한 채로 Web상에 존재하게 되었다 따라서, 이러한 정보들을 체계적으로 정리하고, 이용자들의 구미에 맞게 가공된 정보의 필요성이 대두되게 되었다. 이러한 문제를 해결하기 위해서 이용자가 원하는 것을 스스로 인지하고 판단하여 요구사항을 해결해주는 '지능적 대리인' 또는 '지능을 가진 도우미'라고 일컫는 지능형 에이전트(Intelligent Agent)의 필요성이 대두되었다. 지능형 에이전트는 그 다양한 기능으로 인하여 인터넷에서 매우 중요한 요소로 자리잡게 되었다. 우리나라를 비롯해서 선진 해운국에서는 선박매매사이트를 개설하여 사이버 공간상에서 거래를 수행하고 있지만, 사이트별 등록된 선박의 수가 많지 않을 뿐 아니라 거래대상 선박의 표현 방식도 사이트별 국가별로 매우 달라, 선박 매매 시 충분한 매매대상 선박정보를 획득하기 어려운 실정이다. 본 연구는 선박매매 시 고객에게 매매 선박정보를 제공해주는 선박매매용 에이전트 설계를 목표로 하고 있다. Bargainfinder, Bargainboat, Shopboat, Price watch 등 쇼핑몰을 대상으로 하는 비교쇼핑에이전트는 상용화되어 운영되고 있지만 선박매매용 에이전트에 관한 연구는 시도되지 않고 있다. 본 연구는 선박매매용 에이전트를 개발하기 위한 설계연구로서 다음 사항에 대한 연구가 시도되었다. (a) 구매 선박에 대한 요구사항 표현 방법 (b) 관련 선박의 표현, 등록 및 색인방법 (c) 공급 선박의 분류와 표현 방법 (d) 에이전트의 정보 수집을 위한 메시지 표현 방법 (e) 수집된 선박정보의 데이터베이스 저장 표현방법 (f) 요구 선박을 찾아주는 정보제공 서비스가 요구된다.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.768-772
• /
• 2008

Various scanning systems have been studied in many industrial areas to acquire a range data or to reconstruct an explicit 3D model. Currently optical technology has been used widely by virtue of noncontactness and high-accuracy. In this paper, we describe a 3D laser scanning system developped to reconstruct the 3D surface of a large-scale object such as a curved-plate of ship-hull. Our scanning system comprises of 4ch-parallel laser vision modules using a triangulation technique. For multi laser vision, calibration method based on least square technique is applied. In global scanning, an effective method without solving difficulty of matching problem among the scanning results of each camera is presented. Also minimal image processing algorithm and robot-based calibration technique are applied. A prototype had been implemented for testing.

• Journal of the Society of Naval Architects of Korea
• /
• v.46 no.6
• /
• pp.659-666
• /
• 2009

Recently, there are several problems in space, contiguity and facility of the existing harbors issued due to the trend of enlarging the container capacity of the large container vessel, the Mobile Harbor has been proposed conceptually as an effective solution for those problems. This concept is a kind of transfer loader of the containers from the large container ship, which is a floating barge with a catamaran type in the underwater part, and so prompt maneuverability and work effectiveness. For the safe mooring of two floating bodies, a container and the mobile harbor, in the near sea apart from the quay, a robot arm mooring facility specially devised would be designed and verified through comparison study under various environmental sea condition in the inner and outer harbor. DP system (Dynamic Positioning System) using the azimuth thruster and a pneumatic fender, etc, will be considered as a next research topic for the mooring security of multi-body floaters.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.5
• /
• pp.573-579
• /
• 2021

In this study, flow analysis was performed on three types of strainers for ships with different flow rates to predict the pressure drop of the strainer due to the filter of strainer. In the case of flow analysis, the flow analysis was performed by applying the porous media method by applying the resistance value derived by Ergun's equation to the filter position. As a result of the analysis, it was found that when the dimensions of the strainer body were small, the influence of the flow rate on the pressure drop was large. In addition, the amount of pressure drop and the flow rate are almost linearly proportional, and an analysis formula that can predict the amount of pressure drop was derived. In order to predict the amount of pressure drop of the strainer when blockage exist in the strainer filter, the analysis was performed by introducing the resistance ratio to derive the prediction equation. Using this equation, it is thought that it will be possible to predict the performance of the strainer due to blockage in the future strainer design and field application.

• Journal of the Semiconductor & Display Technology
• /
• v.18 no.1
• /
• pp.117-122
• /
• 2019

Pipes are widely used in various industries such as automobile, anti-vibration devices, factories and ship building. Chamfering is one of the most critical processes in pipe manufacturing which removes burrs of the pipes for better surface quality. In most cases, the defects of the chamfered surface are originated from the structural vibrations of the chamfering machine. In this study, the dynamic characteristics of a chamfering machine have been analyzed though the experiment and the computer simulation. And the effects of the design parameters affecting the stability of the machine have been investigated to stabilize the machine structure and further to reduce structural vibrations. The result shows that design alterations to stabilize the machine can suppress the defects of the machined surface as well as the vibrations during chamfering.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.185-188
• /
• 2009

In this paper, Position Controller for balance of Seesaw System design using PID Algorithm. Seesaw System is that it's system use widely to analyze of ship or flight dynamics, Inverted Pendulumand, Robot System, manage system for theory of modern control system and all sorts of analysis. In case of Seesaw System, it's necessity that understand and analysis of system and correct selection of parameter because the system is strong nonlinear control system. It guarantees efficiency and stability to adapt quickly for disturbance or change of controller from PID Algorithm of guarantee safe from simple and long history and PSO(Particle Swarm Optimization) that sort of metaheuristic optimization that need to accuracy and fast PID parameter tuning.

• Journal of The Korean Association For Science Education
• /
• v.34 no.8
• /
• pp.719-730
• /
• 2014

The purpose of this study was to investigate elementary school students' perceptions about science, engineering and technology and their images of scientists, engineers, and technicians. In order to investigate students' images of scientists, engineers, technicians and student's perception of science, engineering, and technology, we used the tools "Draw a scientist at work, Draw an engineer at work, and Draw a technician at work". We have revised the tool DAST (Draw a scientist test), which was used in Fralick et al.'s study (2009). Subjects were 209 6th grade students sampled from an elementary school in G-city in Korea. According to the results of this study, the students' representative image of a scientist was similar to stereotypical scientist image in previous studies, but the students perceived science as a field of research with various professionals. The students' representative image of an engineer was a man with short hair, no beard or mustache, wearing ordinary clothes but no glasses. The engineer was designing or constructing a ship, a robot, a computer, and an airplane. The students' representative image of a technician was a man with short hair, wearing protective goggles and a mask for welding. The technician was fixing a car, a robot, a rocket, etc. and working with wrenches, hammers, screw drivers, welding machines, etc. Many students didn't perceive engineering and technology as fields of research. Also, many students didn't variously perceive engineering and technology as fields and ways of study.

• Journal of Korea Multimedia Society
• /
• v.12 no.2
• /
• pp.231-243
• /
• 2009

Currently interests of embedded software in various areas such as automotive field, ship field, robot field is increasing according to expand market of embedded systems. Various researches such as embedded operating systems, embedded software modeling technique, embedded software testing, and so on are going in progress. However systematic engineering approach in embedded system development is poor because embedded areas focus on hardware parts until now. Furthermore, framework-based de sign technique considering reusability is not reflected in embedded system development. Those development results in many of dead codes scattered in system, and results in poor reusability of system. This paper suggests a framework of embedded system for reusability and a static meta-model for reuse framework. Proposed meta-model expresses not only the structure of reuse framework, but also allows a designer to extend and design easily models of embedded system based on reuse framework according to various embedded system types.

• Journal of Positioning, Navigation, and Timing
• /
• v.6 no.4
• /
• pp.167-179
• /
• 2017

In this paper, a simplified Cubature Kalman Filter (SCKF) is proposed to reduce the computation load of CKF, which is then used as a filter for transfer alignment of shipboard INS. CKF is an approximate Bayesian filter that can be applied to non-linear systems. When an initial estimation error is large, convergence characteristic of the CKF is more stable than that of the Extended Kalman Filter (EKF), and the reliability of the filter operation is more ensured than that of the Unscented Kalman Filter (UKF). However, when a system degree is large, the computation amount of CKF is also increased significantly, becoming a burden on real-time implementation in embedded systems. A simplified CKF is proposed to address this problem. This filter is applied to shipboard inertial navigation system (INS) transfer alignment. In the filter design for transfer alignment, measurement type and measurement update rate should be determined first, and if an application target is a ship, lever-arm problem, flexure of the hull, and asynchronous time problem between Master Inertial Navigation System (MINS) and Slave Inertial Navigation System (SINS) should be taken into consideration. In this paper, a transfer alignment filter based on SCKF is designed by considering these problems, and its performance is validated based on simulations.