• Journal of radiological science and technology
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• v.43 no.4
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• pp.243-249
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• 2020

Examination with medical radiography is the most significant advances in medicine in the 21st century. Diagnostic imaging occupies an important position in all medical subjects, surgical and internal medicine, including radiology, orthopedics, and neurosurgery. However, the invention associated with conventional radiography devices has focused only on emphasizing the efficient aspects of the examination or obtaining clearer images without considering the age and disease-induced constraints of the patient's posture. The newly developed X-ray aids to solve this problem can effectively perform X-ray imaging of children's who have difficulty communicating and controlling. It is also thought to be a good way to provide accurate imaging information and minimize radiation exposure for children.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.65-77
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• 2017

In this paper, we introduce the pipe cleaning robot developed to clean the gas impurities of the iron manufacturing equipments. The pipe cleaning robot is composed of two driving modules and one cleaning module. 2-DOF joint units were developed for connections among the modules. To maximize the traction power of the driving parts, it became caterpillar type. The extension links have been developed to maintain the traction force in case the pipe inner diameters change. Three cleaning modules were developed for the effective cleaning in the pipe. The driving and cleaning performance tests of the pipe cleaning robot were proceeded in the field of the iron manufacturing equipments.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.87-94
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• 1996

Random wave breaking is one of the most important phenomena in coastal engineering. For two and half decades, various models have been proposed to predict wave height variations in the surf zone. However, some models are applicable to plane beaches only, some requires clumsy computation for a joint probability density of wave heights and periods, and some others need calibration with individual wave data. The present study aims at formulating a model simple enough but reasonably accurate. The merits of the present model are as follows: It is applicable to any shapes of bottom profiles; It requires the input data of incident wave heights and periods only without necessity of coefficient calibration with field data; and its computation time is minimal because it deals with representative waves directly.

• The Journal of Information Technology
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• v.3 no.3
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• pp.39-55
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• 2000

Internet Trade is the new type of business transaction, which sells and advertises the product and services by using the Internet, which is spreaded rapidly to the world. Under these circumstance, our country should discuss the proper position and role as the center in the trade amount in the world trade market, and face the irresistible changes of trade environment. First, in the institution and legal aspect. Second, the price payment system of the internet trade. Third, the so-called infra construction, the physical sector for activating the internet trade, the comprehensive plan of super-highway information communication net work by the government authorities is expected to be promoted. There is no perfect solution that internet trade could be completely done in front of monitor and will be solved one by one along with the development of electronic commerce. At last, the government's and industry's joint positive concern and participation in the rapidly changing new world trade trends of internet trade is expected fit for our position in the world.

• Journal of Korean Society for Quality Management
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• v.42 no.1
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• pp.111-127
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• 2014

Purpose: Simple part or equipment is necessary TRA(Technology Readiness Assessment) or MRA(Manufacturing Readiness Assessment). But sole maturity like TRA, MRA has limit complex systems or SoS(System of System). Especially complex weapon system need from the System Maturity Point of view. This research shows necessity of SRA(System Readiness Assessment). Methods: In case of complex systems, it is essential to SRA(System Readiness Assessment). For the purpose of calculating SRL(System Readiness Level), TRL and IRL must be calculated. And then SRL can obtain know from equation of TRL and IRL. To prove SRA effectiveness, it is calculated SRL of JTDLS(Joint Tactical DataLink System) programs. Results: SRA procedure is proposed and case study shows as examples of JTDLS programs. Although result of TRA is TRL6, result of SRA is not 0.6. From this research, we can know necessity of SRA. Especially complex systems or SoS(System of System) is essential to SRA. Conclusion: SRA(System Readiness Assessment) is required to overcome limitation of sole maturity and to achieve a successful acquisition of high quality weapon system. This research intended to suggest SRA procedure and case study in complex defense system.

• Journal of Welding and Joining
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• v.23 no.5
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• pp.25-29
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• 2005

Steel has been mainly used in the automotive industry, because of good mechanical properties, weldability and so on. However, there has been increase in using aluminum to reduce the weight of vehicle. This leads to improve fuel efficiency and to reduce air pollution. A steel-aluminum hybrid body structure is recently used not only to reduce the weight of vehicle but also to increase safety. In this paper, the laser beam joining method is suggested to join steel and aluminum. To avoid making brittle intermetallic compounds(IMC) that reduce mechanical properties of the joint area, only aluminum is melted by laser irradiation and wetted on the steel surface. The brittle IMC layer is formed with small thickness at the interface between steel and aluminum. By controlling the process parameters, brittle IMC layer thickness is suppressed under 10 micrometers which is a criterion to maintain good mechanical properties.

• Journal of Welding and Joining
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• v.29 no.6
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• pp.49-55
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• 2011

With the development of pre-painted steel sheets for automotive body application, a new joining method is required such as hybrid joining with combination of adhesive bonding and mechanical joining. The objective of this study is to investigate the effect of pre- and post-baking of adhesive bonding on failure mode and strength of hybrid joining of automotive steel sheets. Experiments show that the hybrid joining exhibits better bonding strength and displacement than conventional adhesive joining and mechanical fastening each. Comparison of pre- and post-baked hybrid joining results suggested that baking at $160^{\circ}C$ after mechanical joining was found to have higher joining properties than pre-baking condition. The prebaking condition changed its fracture mode from interfacial to button fracture. The changes in fracture mode with post-baking of hybrid joining was attributed to variation in neck thickness and undercut of joint.

• Journal of Welding and Joining
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• v.25 no.6
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• pp.44-52
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• 2007

A welding process of a lifting lug for lifting heavy objects is one of the important welding processes directly related to the safety in shipbuilding. Welding a lifting lug is done in the manually and takes about forty minutes. Working environment for the lifting lug welding is very poor due to an radiant heat and a harmful fume. The purpose of this study is to develop methods of multi-pass welding using the lifting lug welding robot system. This study shows robot welding methods to achieve proper corner, straight and connection welding and an effectiveness of application.

• Journal of Welding and Joining
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• v.26 no.5
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• pp.66-73
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• 2008

Welding work in pre-erection or erection stage of shipbuilding construction to be carried out in flat and vertical upward position mostly and Electrogas welding(EGW) is actively applied especially for vertical butt joint of thicker steel plate recently. In this study considered how to develope and improve mechanical properties of weld metal and HAZ in high heat input welding processes such as EGW and Electroslag welding(ESW) with its welding equipment in order to extend the application range to the longitudinal members and hatch coaming parts of container ship. Some components of welding system and parameters were modified to get the faster travel speed and reduce weld heat input, and also by adding additional filler rods or tubes increase the amount of deposited weld metal. With the test get some good date can apply to actual fabrication work and recommend items to manufacture welding materials make better. Above all things it's a fruition that to prepare the possibility of application of ESW to shipbuilding construction which fill up the gap of stoppage days of more than 20 years.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.7-16
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• 2011

This study proposes the compensation method for the mechanical deflection error of a SCARA robot. While most studies on the related subject have dealt with the development of a control algorithm for improvement of robot accuracy, this study presents the control method reflecting the mechanical deflection error which is predicted in advance. The deflection at the end of the gripper of SCARA robot is caused by the self-weights and payloads of Arm 1, Arm 2 and quill. If the deflection is constant even though robot's posture and payload vary, there may not be a big problem on robot accuracy because repetitive accuracy, that is relative accuracy, is more important than absolute accuracy in robot. The deflection in the end of the gripper varies as robot's posture and payload change. That's why the moments $M_x$, $M_y$ and $M_z$ working on every joint of a robot vary with robot's posture and payload size. This study suggests the compensation method which predicts the deflection in advance with the variations in robot's posture and payload using neural network. To do this, I chose the posture of robot and the payloads at random, found the deflections by the FEM analysis, and then on the basis of this data, made compensation possible by predicting deflections in advance successively with the variations in robot's posture and payload through neural network learning.