• 한국산업보건학회지
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• 제9권1호
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• 구강회복응용과학지
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• 제37권1호
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• pp.1-15
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• 2021

치과용 재료의 적층가공제작은 기존 제작방식에 비해 복잡한 형태까지 제작할 수 있으며 절삭가공에 비해서도 기구나 재료의 소모가 적어 지속가능성이 장점으로 대두되고 있다. 적층가공 제작은 7가지 방식으로 분류할 수 있는데, 폴리머는 적층가공에 가장 적합한 재료로 용기중합방식으로 제작하며 기존 자가중합방식에 비해 높은 물성과 적합도를 가져 상용화에 더 적합하지만 상대적으로 낮은 강도로 인해 임시수복물로 주로 이용된다. 금속은 PBF (powder bed fusion) 방식을 주로 이용하며 주조방식에 비해 파괴인성과 밀도가 높지만 잔류응력이 높아 이를 제거하기 위한 후처리방식에 대한 연구가 필요하다. 세라믹은 분말과 레진폴리머를 혼합한 재료를 용기중합하는 방식이 일반적이다. 제작 후 폴리머제거나 소결과 같은 후처리 과정이 복잡하다. 상용화되려면 세라믹 적층가공에 의한 결과물의 낮은 강도와 체적정확성이 개선되어야 한다. 적층가공은 어떤 재료이건 공정조건에 따라 물성과 표면환경이 달라지므로 가장 적합한 공정조건을 찾기 위한 연구가 더 많이 필요하다고 사료된다.

• 한국직업건강간호학회지
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• 제22권3호
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• pp.179-190
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• 2013

Purpose: Regular cancer screening for workers can help prevent cancer or allow early treatment, and is thus beneficial in improving health, reducing costs, and increasing companies' productivity. However, there has been little research on cancer screening rates of workers and related factors. The purpose of this study was to identify cancer screening rates and relevant factors among manufacturing workers. Methods: Using a questionnaire, data were collected from 335 workers aged over 40 years recruited from seven manufacturing companies. The collected information included cancer screenings (stomach, colorectal, breast, and cervical), attitude towards cancer screening, and demographic and job characteristics. Results: 72.5% of workers received stomach cancer screening (SCS), and 43% received colorectal cancer screening (CRCS). Among 86 women, 68.6% received breast cancer screening and cervical cancer screening. The attitude towards cancer screening was $29.5{\pm}3.78$. Workers aged over 51, married, and those working in mobile manufacturing were more likely to have undergone SCS. Workers aged over 51, married, those working in mobile manufacturing, those in workplaces with more than 1,001 employees, and those with more positive attitudes toward cancer screening were more likely to have undergone CRCS. Finally, attitude affected cervical cancer screening. Conclusion: Workers in small-sized workplaces had lower cancer screening rates. Thus, follow-up research should assess the health environment of workplaces and develop educational programs on cancer screening that reflect attitudes towards screening.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2017년도 춘계 종합학술대회 논문집
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• pp.103-104
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• 2017

목표: 제조업은 산업 재해가 가장 많이 발생하며, 산업 재해를 예방하기 위해 산업계 근로자가 알고 있는 안전 환경을 연구하는 것이 중요합니다. 방법: 2015년 PSWCI 패널 보고서에 응답한 근로자 중 연구 대상은 남성 1,123명이었다. 연구 대상은 영향을 받는 주관적인 건강을 겪은 후 1년 동안의 고용 상태의 변화에 따라 피험자를 분류하여 분석을 했다. 통계 분석은 SAS 버전 9.4 (SAS Institute Inc., Cary, NC, USA)를 사용하여 수행되었습니다. 결과: 분석 결과에 따르면 제조 산업은 근로자 조건에 따라 경제적 활동과 건강상태에 차이가 있었습니다. 제조업 환경의 역동적인 변화의 측면은 성별과 일시적인 상태와 실업 상태 사이에서 남성이 더 높은 경향을 보였다. 결론: 이 연구의 결과는 제조 업계 종업원들이 느끼는 작업 환경의 안전 수준을 향상시키기 위한 것이다.

• 한국산업보건학회지
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• 제29권3호
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• pp.310-321
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• 2019

Objectives: The purpose of this study was to investigate types and characteristics of chemical substances used in LCD(Liquid crystal display) panel manufacturing process. Methods: The LCD panel manufacturing process is divided into the fabrication(fab) process and module process. The use of chemical substances by process was investigated at four fab processes and two module processes at two domestic TFT-LCD(Thin film transistor-Liquid crystal display) panel manufacturing sites. Results: LCD panels are manufactured through various unit processes such as sputtering, chemical vapor deposition(CVD), etching, and photolithography, and a range of chemicals are used in each process. Metal target materials including copper, aluminum, and indium tin oxide are used in the sputtering process, and gaseous materials such as phosphine, silane, and chlorine are used in CVD and dry etching processes. Inorganic acids such as hydrofluoric acid, nitric acid and sulfuric acid are used in wet etching process, and photoresist and developer are used in photolithography process. Chemical substances for the alignment of liquid crystal, such as polyimides, liquid crystals, and sealants are used in a liquid crystal process. Adhesives and hardeners for adhesion of driver IC and printed circuit board(PCB) to the LCD panel are used in the module process. Conclusions: LCD panels are produced through dozens of unit processes using various types of chemical substances in clean room facilities. Hazardous substances such as organic solvents, reactive gases, irritants, and toxic substances are used in the manufacturing processes, but periodic workplace monitoring applies only to certain chemical substances by law. Therefore, efforts should be made to minimize worker exposure to chemical substances used in LCD panel manufacturing process.

• 기술혁신학회지
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• 제22권3호
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• pp.283-306
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• 2019

본 연구는 기업의 비기술적 혁신 활동이 고용증가에 미치는 효과를 실증 분석하였다. 2016년 한국기업혁신조사의 제조업과 서비스업 자료를 이용하여 조직혁신과 마케팅혁신이 기업의 고용에 미치는 효과를 추정하였다. 추정결과에 따르면 조직혁신과 마케팅혁신의 세부 유형별로 고용효과의 차이가 존재하는 것으로 나타났다. 조직혁신의 경우 업무수행방식의 변화와 업무조직의 변화는 제조업과 서비스업 모두에서 고용증가에 유의한 효과를 발생하지 않는 것으로 나타났다. 반면 외부조직과의 협력은 제조업에서는 기업의 고용을 증가시키는 효과가 있는 것으로 나타났다. 마케팅혁신도 제품수요와 연관이 있는 새로운 홍보방식과 신규 판매전략은 제조업의 고용을 증가시키는 효과가 있는 것으로 나타났다. 하지만 서비스업에서는 마케팅혁신이 추가적인 고용효과를 발생하지는 않는 것으로 나타났다.

• Design & Manufacturing
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• 제15권1호
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• pp.48-56
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• 2021

The quality of products produced by injection molding process is greatly influenced by the process variables set on the injection molding machine during manufacturing. It is very difficult to predict the quality of injection molded product considering the stochastic nature of manufacturing process, because the process variables complexly affect the quality of the injection molded product. In the present study we predicted the quality of injection molded product using Artificial Neural Network (ANN) method specifically from Multiple Input Single Output (MISO) and Multiple Input Multiple Output (MIMO) perspectives. In order to train the ANN model a systematic plan was prepared based on a combination of orthogonal sampling and random sampling methods to represent various and robust patterns with small number of experiments. According to the plan the injection molding experiments were conducted to generate data that was separated into training, validation and test data groups to optimize the parameters of the ANN model and evaluate predicting performance of 4 structures (MISO1-2, MIMO1-2). Based on the predicting performance test, it was confirmed that as the number of output variables were decreased, the predicting performance was improved. The results indicated that it is effective to use single output model when we need to predict the quality of injection molded product with high accuracy.

• 한국건설관리학회논문집
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• 제23권1호
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• pp.113-117
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• 2022

적층제조(AM, 일명 3D프린팅)기술은 디자인 자유도가 높고 디지털화된 기술의 특성으로 품질데이터의 예측·관리가 용이한 형태로 존재한다. 이러한 이점으로 AM기술은 다양한 산업에 적용되고 있다. 특히 건축물과 기반시설을 AM기술로 제조하는 방법이 건설 산업에 제안되고 있다. 다만, 다소 부족한 기술의 역사와 품질 및 시공 관리방법의 미비, 제조상품의 인증과 같은 문제로 인해 기술사용이 제한되고 있다. 따라서 간접적인 형태로 AM기술을 활용하여 건축 상품제조를 구현하고 있다. 특히, 거푸집을 적층 제조하고 건축 소재를 투입하여 상품으로 구현하는 방법이 확인되고 있다. 본 연구에서는 대형크기의 거푸집을 적층제조하고 건축 상품을 구현하기 위해 하이브리드 압출적층제조를 활용한다. 또한, 적층제조과정에서 생산성과 경제성을 예측할 수 있는 인자를 확인한다. 결과적으로, 건축물의 구현결과와 생산 비용과 시간을 줄이기 위한 형상설계 최적화 방법을 제안한다.

• Journal of Preventive Medicine and Public Health
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• 제32권1호
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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.

• 한국안전학회지
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• 제37권5호
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• pp.42-55
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• 2022

In this study, an accident at an in-house maintenance subcontractor of a manufacturing company was analyzed using representative systemic analysis methods, and the results were compared to determine the socio-technical and organizational structure causal factors. Systemic accident analyses were performed using AcciMap, STAMP-CAST, and a method that utilizes work processing procedures. The causal factors derived from the three methods were classified according to HFACS classification criteria. AcciMap and STAMP-CAST analyses were able to derive legal problems and defects in organizational structure between the company and the subcontractors. The method that utilized the work processing procedures drew the most causal factors of the three methods but showed some limitations in deriving legal and facility-related problems. Most of the causal factors identified through the systemic methods could be classified according to the HFACS classification criteria, except for the legal and organizational structure matters. Socio-technical and organizational problems with a holistic perspective of the company and subcontractors could be found using systemic analysis methods. However, it is necessary to conduct analysis using various methods in order to derive more comprehensive measures to prevent accidents because each analysis method showed some limitations in the derivation or expression of some causal factors. The results of this study can be helpful in selecting and using an appropriate method for accident analysis.