• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.107-116
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• 2024

Copper Filter Dryer (CFD) are responsible for removing impurities from the circulation of refrigerant in refrigeration and cooling systems to maintain clean refrigerant, and defects in CFD can lead to product defects such as leakage and reduced lifespan in refrigeration and cooling systems, making quality assurance essential. In the quality inspection stage, human inspection and defect judgment methods are traditionally used, but these methods are subjective and inaccurate. In this paper, YOLOv7 object detection algorithm was used to detect defects occurring during the CFD Shaft pipe and welding process to replace the existing quality inspection, and the detection performance of F1-Score 0.954 and 0.895 was confirmed. In addition, the cause of defects occurring during the welding process was analyzed by analyzing the sensor data corresponding to the Timestamp of the defect image. This paper proposes a method for manufacturing quality assurance and improvement by detecting defects that occur during CFD process and analyzing their causes.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.520-526
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• 2015

Reinforcing bar splices are inevitable in reinforced concrete structure. In these days, there are three main types of splices used in reinforced concrete construction site - lapped splice, mechanical splice and welded splice. Low cost, practicality in construction site, less time consuming and high performance make gas pressure welding become a favorable splice method. However, reinforcing bar splice experiences thermal loading history during the welding procedure. This may lead to the presence of residual stress in the vicinity of the splice which affects the fatigue life of the reinforcing bar. Therefore, residual stress analysis and tensile test of the gas pressure welded splice are carried out in order to verify the load bearing capacity of the gas pressure welded splice. The reinforcing bar used in this work is SD400, which is manufactured in accordance with KS D 3504. The results show that the residual stresses in welded splice is relatively small, thus not affecting the performance of the reinforcing bar. Moreover, the strength of the gas pressure welded splice is high enough for the development of yielding in the bar. As such, the reinforcing bar with gas pressure welded splice has enough capacity to behave as continuous bar.

• Journal of Conservation Science
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• v.34 no.2
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• pp.87-96
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• 2018

This study analyzed the influence of folding time on the forge welded bar and hammer scale produced using the traditional refining and forge welding reproduction experiment. In the case of the forge welded bar, increasing the forging time decreased the percentage of impurities and porosity from 26.09% to 1.8%. Additionally, the hardness increased by an average of 36.88 HV. In other words, the microstructure gradually became more precise. For the hammer scale, the amount of T Fe increased with forging time. X-ray diffraction analysis revealed the presence of quartz, fayalite, $w{\ddot{u}stite$, and magnetite. The amount of quartz decreased as the forging time increased. In addition, as the forging time increased, the granular $w{\ddot{u}stite$ changed into a cohesive, long, white band. The results provide information on the characteristics of the forge welded bar and hammer scale produced in the refining and forging process. This information can be used as technical data for ancient steel making processes as well as for future technological systems.

• Journal of Ship and Ocean Technology
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• v.12 no.3
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• pp.1-13
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• 2008

In shipbuilding, diverse manufacturing techniques for automation have been developed and used in practice. Among them, however, the hull forming automation is the one that has not been of major concern compared with others such as welding and cutting. The basis of the development of this process is to find out how to extract thermal forming information. There exist various methods to obtain such information and the 3D design shape that needs to be formed should be extracted first for getting the necessary thermal forming information. Except well-established shipyards which operate 3D design systems, most of the shipyards only rely on 2.5D design systems and do not have an easy way to obtain 3D surface design data. So in this study, various shipbuilding design systems used by shipyards are investigated and a 3D design surface data extraction method is proposed from those design systems. Then an example is presented to show the extraction of real 3D surface data using the proposed method and computation of thermal forming information using the data.

• Journal of Korean Library and Information Science Society
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• v.9
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• pp.213-240
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• 1982

Today, one of the major pressures that libraries have been facing is the rapid growth of publications. Due to the rapid growth of publications, libraries have been faced the shortage of stack as well as quality deterioration of library collections. Naturally, these disa n.0, ppointed the users and made the present library activities weak and inadequate. One of the desirable actions in remedying these problems is to weed library collections properly and regularly. Weeding methods used in libraries are derived from the judgement by subject specialists, from the examining the imprint date and the past use patterns of a volume. Among these methods, the past use patterns are highly predictive of the future use, and can be used to create meaningful weeding criteria. Since the libraries in Korea have emphasized on numbers of library collection in the past, the libraries have neglected weeding library collections. Now, we must turn our concern toward the weeding library collections, and the attitude of the library services to the users must change from passive to active.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.1
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• pp.13-17
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• 2017

The sectors of the Root industry include casting, plastic works, welding, surface treatment, and heat treatment. While the industry is concerned with the processing technologies that are used in most of the manufacturing industries, the sophistication of the corresponding manufacturing information systems is very low. This paper describes a manufacturing information system for the building sector for which the smartphone devices that the workers use in their daily lives are employed, and where the cost of the adaption of the manufacturing system at their factories is minimized. The proposed system consists of the following three parts: UI composer, General Application, and Gateway.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.91-93
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• 2005

Forming sheet metal by laser-induced thermal stresses (laser forming) has been extensively studied, and the research has focused on two-dimensional geometries using a multi-pass straight line scan. Recently there came out some useful studies or three-dimensional laser forming which is applied to doubly curved shapes. The task of 3D laser forming sheet metal is to determine a set of process parameters such as laser scanning paths, laser power and scanning speed that will make a given shape. New method for laser forming of a doubly curved surface by using geometrical information was proposed and verified by experiments. This method shows good performance in the sense of calculation time and accuracy compared to the inherent strain method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.494-497
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• 1999

Neural networks are shown to be effective in being able to distinguish incomplete penetration-like weld defects by directly analyzing the plasma which is generated on each impingement of the laser on the materials. The performance is similar to that of existing methods based on extracted feature parameters. In each case around 93% of the defects in a database derived from 100 artificially produced defects of known types can be placed into one of two classes: incomplete penetration and bubbling. Especially we present simulator for weld defects classification and data analysis. The present method based on classification using plasma is faster, and the speed is sufficient to allow on-line classification during data collection.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.291-293
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• 2014

실시간 용접공정 모니터링 시스템은 기존 용접시스템에서 발생할 수 있는 오류를 감소시키고 관리하기 위한 시스템으로 오류 발생 시 실시간으로 담당자에게 정보를 제공하여 빠르게 오류를 수정할 수 있게 한다. 또한 오류의 범위를 유동적으로 설정하게 하여 시스템 사용자가 쉽게 사용이 가능하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1074-1075
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• 2023

용접작업은 다양한 산업에서 이루어지는 중요한 작업인데 반해, 여러 가지 위험요소들로 인해 작업자의 건강에 위협을 가할 수 있다. 또한, 용접 작업자들을 효율적으로 관리할 수 있는 안전점검인력이 부족한 실정이다. 이에 본 논문은 항만 용접 작업자의 안전을 위한 스마트헬멧 제작과 연동 APP을 개발하여, 체계적으로 작업자의 건강을 관리하고 안전사고를 미연에 방지하는 데에 그 목적이 있다.