• Journal of Environmental Health Sciences
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• v.28 no.4
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• pp.12-16
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• 2002

Workers' exposure to lead particles with diverse characteristics was assessed using personal cascade impactors in four different industries. Correlation analyses found that total airborne lead (PbA) concentrations could not explain the variation on MMAD of lead particles. From regression analysis, the concentrations of lead particles smaller than 1 um in AD were found to rise very slowly with increases in total PbA. They rarely contributed more than 50 ㎍/㎥ of total PbA over the range of 5.6-7,740 ㎍/㎥ although there are a few high values greater than 100 ㎍/㎥ while respirable lead concentrations significantly increased with increasing total PbA concentrations. In the secondary smelting and radiator manufacturing industries requiring high temperatures, the average fraction of respirable concentration in total PbA was 43.3% and 48.9%, respectively, which indicated an important contribution to the total PbA. In lead powder and battery manufacturing, it was less than 27%. Our study results concluded that workers' exposure to lead particles with diverse characteristics might not be effectively monitored by the current total PbA sampling alone. To protect workers exposed to different sizes of lead particles generated in many operations, an occupational standard for respirable lead particles should be added to the current total lead standard.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.71-81
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• 2000

This paper describers a look ahead algorithm of PC-NC(personal computer numerical control). The algorithm is based on acceleration/deceleration before interpolation which doesn\`t include a command error and determines a feedrate value at the end point of each block(or start point of each block). The algorithm is represented as following; 1) calculating two maximum arrival feedrates(F$_1$,F$_2$) by an acceleration value, a command feedrate, and the distance of a NC block, 2) getting a tangent feedrate (F$_3$) of the adjacent blocks, 3) choosing a minimum value among these three feedrates, and 4) setting the value to a feedrate of a start point of the next block(or a end point of the previous block). The proposed look ahead algorithm was implemented and tested by using a commercial TROS(real time operation system) on the MS-Windows NT 4.0 in a PC platform. For interfacing to a machine, a counter board, a DAC board and a DIO board were used. The result of the algorithm increased a machining precision and a machining speed in many short blocks.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.41-48
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• 2019

The industrial safety helmets are personal protective equipment (PPE), used to protect the head against falls from a height. This study indicated the necessity of wearing a safety helmet while working at heights below 4 m, through analysis of fall accidents occurring in the industrial field. The stress, displacement, and strain of the safety helmet shell structure have been analyzed using the finite element method with various thicknesses, engineering plastics, and designs. It was preferred that the safety helmet shell structure had a reinforcement frame of uniform thickness in terms of increased impact strength and strain energy absorption rate. The thickness can be reduced to lighten the total weight for workers wearing safety helmets.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.105-112
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• 2020

The increase in the edentulous jaw which occurs in the aged population has led to personal dental health concerns. In the case of dental implant surgery, the duration of a patient's recovery depends on the surgical plan and their physicical ability. A device may be required to assist a physician in controlling vibration reduction of free-hand drilling and prescribing a good treatment plan that is suitable for the patient's condition. In this work, an artificial tooth-root implant assistant manipulator was studied. The structure and the vibration analysis of the dynamic restraint manipulator that is for drilling the alveolar bone in the mandible bone were performed, and the structural stability was analyzed. Further, a virtual prototype of an artificial tooth-root implant assisted manipulator was fabricated and tested. Hence, the state of the Remote Center of Motion (RCM) point and the driving state of the manipulator were confirmed. Furthermore, the drilling experiments were performed by using materials similar to a human jawbone in order to evaluate the performance of the drilling process that is operated using the assistant manipulator.

• Journal of Preventive Medicine and Public Health
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• v.32 no.1
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• pp.17-29
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• 1999

Objectives. This study was carried out to analyze the hearingthreshold levels and relating factors of 1,048 workers with noiseinduced hearing loss$(D_1)$. Methods. We analyzed the hearing-threshold levels and relating factors of 1,048 workers with noise-induced hearing loss$(D_1)$ examined by the summary reports of specific health examination results of industries and personal reports of specific health examination results reported by 58 specific health examination institutes and 8 secondary pneumoconiosis examination institutes in 1996. Results. Among 1,048 workers at 510 workplaces, male workers were 1,009 (96.3%) and female workers were 39 (3.7%). The mean ages of workers initially exposed to noise and at present were 28.7 and 47.2, respectively. The duration of total exposure was 16.5 years. Average hearing-threshold levels analyzed by three-divided classification of the study subjects were 43.7dB(Lt) and 42.6dB(Rt). Those analyzed by six-divided classification were 50.5dB(Lt) and 48.6d8(Rt). Among workers with noise-induced shearing loss$(D_1)$, 16.3% was unilateral hearing loss and 84.6% was classified to compensation case. 8.8%(Rt) and 10.2%(Lt) of them were suspected to be conductive hearing loss by differences of air-bone hearing-threshold levels. Hearing-threshold levels of workers in manufacturing industry were significantly increased during the short exposure compared with the levels in mining industry. Among manufacturing industries, hearing-threshold levels of workers in trailer and other transportation equipment manufacturing industry were significantly increased. Age and duration of total noise exposure were not significantly related to the average hearing-threshold levels analyzed by three-divided classification. Hearing-threshold levels of female workers were significantly increased during the short exposure compared with those of male workers. Hearing-threshold levels of workers at the high risk group, ages of 20s, 30s and total exposure duration of less than 10 years, were not significantly increased compared with those of the other groups. However, they were exposed at young ages. The 3 leading industries of workers at high risk group were trailer and other transportation equipment manufacturing, automobile manufacturing and assemble-metal manufacturing industries. Conclusions. This study was the first nationwide analysis of the hearing-threshold levels and relating factors of workers with noise. induced hearing loss$(D_1)$. We found the differences of the real number by the statistics of the department of labour and the expected number of worker' s compensations for occupationally-induced hearing loss estimated by this study. According to the results of this study, we should carefully examine the methods to narrow this difference.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1261-1262
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• 2008

Laser-based crystallization techniques are ideally-suited for forming high-quality crystalline Si films on active-matrix display backplanes, because the highly-localized energy deposition allows for transformation of the as-deposited a-Si without damaging high-temperature-intolerant glass and plastic substrates. However, certain significant and non-trivial attributes must be satisfied for a particular method and implementation to be considered manufacturing-worthy. The crystallization process step must yield a Si microstructure that permits fabrication of thin-film transistors with sufficient uniformity and performance for the intended application and, the realization and implementation of the method must meet specific requirements of viability, robustness and economy in order to be accepted in mass production environments. In recent years, Low Temperature Polycrystalline Silicon (LTPS) has demonstrated its advantages through successful implementation in the application spaces that include highly-integrated active-matrix liquid-crystal displays (AMLCDs), cost competitive AMLCDs, and most recently, active-matrix organic light-emitting diode displays (AMOLEDs). In the mobile display market segment, LTPS continues to gain market share, as consumers demand mobile devices with higher display performance, longer battery life and reduced form factor. LTPS-based mobile displays have clearly demonstrated significant advantages in this regard. While the benefits of LTPS for mobile phones are well recognized, other mobile electronic applications such as portable multimedia players, tablet computers, ultra-mobile personal computers and notebook computers also stand to benefit from the performance and potential cost advantages offered by LTPS. Recently, significant efforts have been made to enable robust and cost-effective LTPS backplane manufacturing for AMOLED displays. The majority of the technical focus has been placed on ensuring the formation of extremely uniform poly-Si films. Although current commercially available AMOLED displays are aimed primarily at mobile applications, it is expected that continued development of the technology will soon lead to larger display sizes. Since LTPS backplanes are essentially required for AMOLED displays, LTPS manufacturing technology must be ready to scale the high degree of uniformity beyond the small and medium displays sizes. It is imperative for the manufacturers of LTPS crystallization equipment to ensure that the widespread adoption of the technology is not hindered by limitations of performance, uniformity or display size. In our presentation, we plan to present the state of the art in light sources and beam delivery systems used in high-volume manufacturing laser crystallization equipment. We will show that excimer-laser-based crystallization technologies are currently meeting the stringent requirements of AMOLED display fabrication, and are well positioned to meet the future demands for manufacturing these displays as well.

• Convergence Security Journal
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• v.16 no.7
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• pp.173-180
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• 2016

There has been a growing interest in automation of factories in the country. And, the development in this regard has been actively attempted. In particular, on the basis of the "innovation 3.0 strategy of manufacturing industry", interest in the smart of the manufacturing plant of small and medium-sized enterprises has increased rapidly. As well as policy for building smart plant, technical, seeking a strategic approach. But, in order to introduce such a smart plant or factory automation systems, manufacturing plant security with vulnerability and personal information protection problems, it should always be top priority there. Accordingly, we provide the applicable lightweight secure protocols in RFID communication. It is a wireless communication technology that is most often introduced for factory automation. Our proposed lightweight secure protocol in this study, less the number of calculations in comparison with the existing public key-based and the symmetric key encryption algorithm. And it is fast in compare with the existing protocol. Furthermore, we design that it system can support to low power consumption and small consume the memory size.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5792-5799
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• 2013

The purpose of this study was the Application of the HACCP (Hazard Analysis Critical Control Point) system to Korean Rice Cakes. Main ingredients of rice cakes, work facilities and workers were provided from KB company located in Seogye-dong Yongsan-gu, Seoul between September 12, 2012 and February 13, 2013. The manufacturing process chart was prepared by referring to the manufacturing process of rice cake manufacturers in general. As a result of this study, the microbiological hazard analysis on raw materials and finished products of rice cakes showed safe result. However, microorganism test on the manufacturing environment and workers suggested that microbiological hazard should be reduced through systematic cleaning and disinfection, accompanied by improved personal hygienes based on hygienic education on workers and management of microorganisms in the air.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.805-807
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• 2016

By using ICT in the manufacturing industry with the advent of "Industry 4.0" of Germany, it has been promoted a lot of research to maximize the production capacity. Be particularly increased manufacturing complexity, increase the information delivered to the operator, augmented reality technologies in order to maximize production have been studied. In this paper, in order to solve the deficiencies problem that frequently occurs in the actual site, using the augmented reality technology, provides a system for providing personal training information to the worker. Proposed system, by fusing worker information and process another job, generates educational information of the individual, it is to provide information through the video of the tablet. When using such methods, it is expected that it is possible to improve the production quality of the manufacturing industry to overcome the deficiencies problem that frequently occurs through the continuing education of employees.

• Convergence Security Journal
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• v.17 no.2
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• pp.153-158
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• 2017

The robot imitates humans and recognizes the external environment and judges the situation. The robot is a machine that operates autonomously. Robots are divided into manufacturing robots and service robots. Service robots are classified as professional service robots and personal service robots. Because of the intensified competition of productivity in manufacturing industries, rising safety issues, low birth rate and aging, the robots industry is emerging. Recently, the robot industry is a complex of advanced technology fields, and it is attracting attention as a new industry where innovation potential and growth potential are promising. IT, BT, and NT related elements are fused and implemented, and the ripple effect is very large. Due to changes in social structure and life patterns, social interest in life extension and health is increasing. There is much interest in the medical field. Now the artificial intelligence (AI) industry is growing rapidly. It is necessary to secure global competitiveness through strengthening cooperation between large and small companies. We must combine R&D investment capability and marketing capability, which are advantages of large corporations, and robotic technology. We need to establish a cooperative model and secure global competitiveness through M&A.