• 한국기계가공학회지
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• 제15권5호
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• pp.39-47
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• 2016

Nowadays, several welding processes are generally used to join parts together, and the materials are generally steel, aluminum, copper, stainless steel, and other difficult-to-weld materials. If a proper welding process is chosen, it is helpful for welding parts. However, there is no desirable technique for appropriately deciding on the welding process in the industry. Therefore, an appropriate method of selecting a welding process is needed for the novice worker in the industry. In this sense, a new analytic network process (ANP) technique is used for effective decision making in welding. By considering several criteria in ANP, a selection method is suggested to decide on the proper welding process. In the study, several criteria were considered for the proper welding of parts. By considering a matrix of prior interdependence effects among various welding processes, a decision-making method based on an ANP is accomplished using a weighting matrix, which is supposed to select an appropriate welding process. In addition, for appropriate decision criteria of the welding process, several factors, such as material, shape, precision, economics, and equipment, are used to accomplish the ANP algorithm. Moreover, the final weighting matrix is calculated following its ANP strategy. Furthermore, this decision-making technique is applied to both stainless razor spot joining and thick steel pipe joining. The results show its reliability and practicality, and the novice engineer and manager can use this technique to determine the best welding process.

• 산업경영시스템학회지
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• 제42권3호
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• pp.25-38
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• 2019

This study is to develop a diagnostic model for the effective introduction of smart factories in the manufacturing industry, to diagnose SMEs that have difficulties in building their own smart factory compared to large enterprise, to identify the current level and to present directions for implementation. IT, AT, and OT experts diagnosed 18 SMEs using the "Smart Factory Capacity Diagnosis Tool" developed for smart factory level assessment of companies. They analyzed the results and assessed the level by smart factory diagnosis categories. Companies' smart factory diagnostic mean score is 322 out of 1000 points, between 1 level (check) and 2 level (monitoring). According to diagnosis category, Factory Field Basic, R&D, Production/Logistics/Quality Control, Supply Chain Management and Reference Information Standardization are high but Strategy, Facility Automation, Equipment Control, Data/Information System and Effect Analysis are low. There was little difference in smart factory level depending on whether IT system was built or not. Also, Companies with large sales amount were not necessarily advantageous to smart factories. This study will help SMEs who are interested in smart factory. In order to build smart factory, it is necessary to analyze the market trends, SW/ICT and establish a smart factory strategy suitable for the company considering the characteristics of industry and business environment.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.699-706
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• 2022

In this study, Directed energy deposition (DED) among additive manufacturing is applied to repair damaged spindle key parts of planner miller. The material of the spindle key is SCM415, and the P21 Powder is used. In order to find the optimal deposition conditions for DED equipment, a single-line deposition experiment is conducted to analysis five parameters. The laser power affects the width, and the height is a parameter affected by coaxial gas and powder gas. In addition, laser power, powder feed rate, coaxial gas, and powder gas are parameters that affect dilution. Otimal deposition is that 400 W of laser power, 4.0 g/min of powder feed rate, 6.5 L/min of coaxial gas, 3.0 L/min of powder gas and 4.5 L/min of shield gas. By setting the optimum conditions, a uniform deposition cross section in the form of an ellipse can be obtained. Damage recovery process of spindle key consists of 3D shape design of the base and deposition parts, deposition path creation and deposition process, and post-processing. The hardness of deposited area with P21 powder on the SCM415 spindle key is 336 HV for the surface of the deposition, 260 HV for the boundary area, and 165 HV for the base material.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4512-4526
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• 2018

The Internet of Things (IoT) has become an emerging industry that is broadly used in many fields from industrial and agricultural manufacturing to home automation and hospitality industry. Because of the sheer number of connected devices transmitting valuable data, the IoT infrastructures have become a main target for cyber-criminals. One of the key challenges in protecting IoT devices is the lack of security measures by design. Although there are many hardware and software based security solutions (firewalls, honeypots, IPDS, anti-virus etc.) for information systems, most of these solutions cannot be applied to IoT devices because of the fact that IoT devices have limited computing resources (CPU, RAM,). In this paper, we propose a honeypot system called HoneyThing for modem/router devices (i.e. a kind of IoT device). HoneyThing emulates TR-069 protocol which is prevalent protocol used to remotely manage customer-premises equipment (CPE) devices, e.g. modems, routers. Honeything also serves an embedded web server simulating a few actual, critical vulnerabilities associated with the implementation of TR-069 protocol. To show effectiveness of the HoneyThing in capturing real world attacks, we have deployed it in the Internet. The obtained results are highly promising and facilitate to reveal network attacks targeting to CPE devices.

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.605-613
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• 2023

The multi-axis combined machining technology has enabled combined machining, which was difficult. However, the reality is that manufacturing costs are rising due to expensive equipment and there is a shortage of machine operation engineers. The purpose of this research is to present the optimum cutting conditions for the surface roughness when processing the inner diameter of SUS440C, which is an egg material, using a CNC automatic lathe. As a result of measuring the surface roughness, dry machining was the best at R_a0.481㎛ at a spindle speed of 4,000rpm, a feed rate of 0.05rev/min, and a cutting depth of 0.3mm. In wet machining, the highest value was R_a0.317 at a spindle speed of 2,000 rpm, a feed rate of 0.05 rev/min, and a cutting depth of 0.2 mm. The lower the feed rate, the better surface roughness appears. It was found that the feed rate had more influence than the number of revolutions and depth of cut.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.757-763
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• 2023

Major industrial accidents in which workers die due to fires or explosions while working at chemical substance handling workplaces continue to occur. Among the major industrial accidents that occurred between 2005 and 2021, the accident status by work situation and equipment was analyzed. Through analysis, it was confirmed that storage, reaction, and piping facilities were the main causes of the accident, and a self-checklist for each facility was developed. Verification was conducted through the supply and use groups to evaluate the suitability of the use, duties, and items of the self-checklist. The user group showed higher satisfaction than the supplier group for all three suitability of use, job, and item. In particular, since the inspection items of the self-checklist were organized around the cause of the accident derived through the analysis of actual accident cases, the satisfaction level was high in all groups. It is expected that the self-checklist developed through this study will be useful not only for large companies but also for small and medium-sized chemical industries that lack professional manpower.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.612-618
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• 2020

최근에 외부 유리창 청소에 대한 수요는 증가하고 있으나, 이 청소는 매우 위험한 인력 의존형 작업이다. 또한 청결을 중시하는 업장에서 원하는 빈도로 자주 청소하는 것도 용이하지 않다. 따라서 이 작업을 자동화 할 필요가 있다. 본 연구에서는 특정 유리창에 부착하여, 그 유리창을 지속적으로 청소하는 장치의 개념을 제시하고, 이 장치의 경제적 타당성을 분석하였다. 분석 결과, 장비의 예상 제작비 1천만 원 수준이나, 투자 가능비용은 내구연한 5년 기준으로 최소 9.8백만 원, 내구연한 10년 기준으로 최소 103백만 원 수준이었다. 따라서 장비비 보다 예상 절감액이 충분히 커서, 경제적 타당성이 있는 것으로 평가 되었다. 본 연구에서는 정량적 지표만으로 분석하여, 안전성 향상에 의한 노무자 안전 사고 감소, 생산성 향상, 공기 단축, 품질 향상 등으로 인한 원가 절감 기대 값은 고려되지 않았다는 한계가 있다. 따라서 향후 고려되지 않은 기대 값을 추가하여 자동화 장비에 의한 원가절감 효과를 산출하면 경제성이 보다 정확하게 산정될 것으로 예상된다.

• 한국안전학회지
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• 제38권3호
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• pp.27-34
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• 2023

With the technological development of the semiconductor industry, the roles of electrical and thermal energy supply and control of semiconductor equipment in ultrafine processes have become very important. However, instances of electrical fires in the chiller heater, which is used for cooling in the semiconductor manufacturing process, are increasing. A fire occurs in combustibles due to high heat at the connection part of the chiller heater, that is, when the number of electrical wires in the connection part is reduced or when the wires are completely disconnected. In this study, the temperature characteristics were compared and analyzed through experiments and 3D simulations. The number of electrical wires, which is the connection part of the chiller heater, was reduced by 90%, 50%, 30%, 10%, and 5%, and the wires were completely disconnected. When the number of electrical wires was reduced by 5%, heat of up to 80℃ was generated, which is a relatively high temperature but insufficient to cause a fire in combustibles. Complete disconnection occurred due to the vibration of the motor and other components, and sparks and arcs were generated, resulting in a rapid increase in temperature to up to 680℃. When completely disconnected, the temperature increase was sufficient to cause a fire in the combustibles covering the terminal block. Therefore, in this study, the causes of electrical fires in chiller heaters were investigated and preventive measures were proposed by analyzing abnormal signals and thermal characteristics caused by the electrical wiring being reduced and completely disconnected.

• 한국의류학회지
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• 제31권9_10
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• pp.1442-1452
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• 2007

During 40 years, clothing industry which took a charge of a pivotal role to lead Korea's economy development falls in a harsh state to maintain an international competitiveness by means of low wage-based-export and tech-deficit-past competitive advantage. From January first 2005 when the World Trade Organization started that developed countries abolished import quota on textile and apparel products. Therefore, the purpose of this study is to analyze Korea's apparel international market share, grasp Korea's apparel international competitiveness position, and examine the export features to enhance international competitiveness. We targeted members of Korea Apparel Industry Association among the 500's exporters of textile and clothing items in 'The Import and Export Textile Product 2003' Total 70 sheets were used of final data analyzing. Also, the statistical data of WTO wereselected for inquiry about the position of international competitiveness of clothing products made in Korea. First, the comparative analysis of the amount of export and international market share of each country's clothing products to capture the position of Korea's international competitiveness of clothing industry under the statistical data of WTO showed that Korea's international market share has been decreasing since 1989, and ranked in the 19th showing 1.31% in 2004. Second, as concerned with Korea's clothing export features, the experience of clothing companies in Korea was uniformly distributed like less than 10 to 30 and more than 30 years and knitted and woven male and female wears which cost mid price were exported to U.S.A. and Europe and Japan. Export items wereusually manufactured by Original Equipment Manufacturing way and directly exported through an exclusive responsible part for export.

• 한국정밀공학회지
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• 제27권7호
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• pp.28-35
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• 2010

In the display industry, COG bonding method is being applied to production of LCD panels that are used for mobile phones and monitors, and is one of the mounting methods optimized to compete with the trend of ultra small, ultra thin and low cost of display. In COG bonding process, electrical characteristics such as contact resistance, insulation property, etc and mechanical characteristics such as bonding strength, etc depend on properties of conductive particles and epoxy resin along with ACF materials used for COG by manufacturers. As the properties of such materials have close relation to optimization of bonding conditions such as temperature, pressure, time, etc in COG bonding process, it is requested to carry out an in-depth study on characteristics of COG bonding, based on which development of bonding process equipment shall be processed. In this study were analyzed the characteristics of COG bonding process, performed the analysis and reliability evaluation on electrical and mechanical characteristics of COG bonding using ACF to find optimum bonding conditions for ACF, and performed the experiment on bonding characteristics regarding fine pitch to understand the affection on finer pitch in COG bonding. It was found that it is difficult to find optimum conditions because it is more difficult to perform alignment as the pitch becomes finer, but only if alignment has been made, it becomes similar to optimum conditions in general COG bonding regardless of pitch intervals.