• Safety and Health at Work
• /
• v.10 no.2
• /
• pp.229-236
• /
• 2019

Background: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. Methods: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. Results: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from $4.1{\times}10^{10}$ (Ultem filament) to $2.2{\times}10^{11}$ [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (${\mu}g/min$) ranged from $1.9{\times}10^4$ (acrylonitrile butadiene styrene and polycarbonate) to $9.4{\times}10^4$ (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open ($2.3{\times}10^{10}number/min$) than when the lid was closed ($1.5-5.5{\times}10^9number/min$); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. Conclusion: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial-scale AM process emissions and exposures.

• Journal of Korean Society of Forest Science
• /
• v.108 no.3
• /
• pp.341-348
• /
• 2019

In order to reduce the safety risk of forestry operations, this research was conducted to examine the suitability of chainsaw protective pants after repeated laundering, testing four different products that are currently used in hand-held chainsaw operations. Laundering was repeated 10, 20, 30, 40, and 50 times. After washing, we measured the shrinkage ratio of 17 measurement positions mostly affecting the safety of forest operations and suggested the expected safety life cycle of chainsaw protective clothes. The results showed that most of the products have only one measurement position where the standard shrinkage ratio (<6%) was exceeded after 20 washings, and that the lateral direction of measurement positions shrank more than the vertical one. The numbers of repeated launderings and measurement positions were found to be significant factors influencing the shrinkage ratio (p<0.05). In the shrinkage rates for 17 measurement positions, there were significant correlations between five of the measurement positions (a, b, g, j, and n) and the number of repeated launderings (p<0.05). Therefore, the results suggest that about 10 months would be suitable for an adequate safety lifetime for chainsaw protective pants. The relationship between the number of repeated launderings and the measurement positions will be further analyzed in detail to examine the durability of chainsaw protective pants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.9
• /
• pp.93-102
• /
• 2019

This study examined the nurse's emotional exhaustion and influencing factors, and the relationship between emotional burnout and hospital nursing workload using multilevel logistic regression analysis. The study subjects were 3,083 nurses of 65 hospitals, who participated in the training conducted by the Healthcare Industry Trade Union in 2010 and responded to the questionnaire. First, 71.6% of nurses experienced emotional exhaustion, and the average score of emotional exhaustion was 33.53. Second, the 'non - nursing work experience' showed a significant effect on emotional exhaustion. Third, the 'sufficient nursing staff' variable increased the emotional exhaustion. Fourth, the nursing grades were correlated significantly with emotional exhaustion compared to those with more than four beds per nurse. Fifth, in the case of working in the internal ward, the shorter the clinical career, the higher the emotional exhaustion. In other words, higher emotional exhaustion was associated with more nursing work experience, more perceived insufficient nursing staff, more nurses per bed, the department of internal medicine, and a shorter clinical career.

• Management & Information Systems Review
• /
• v.38 no.3
• /
• pp.127-136
• /
• 2019

With frequent incidents of unethical practices and acts in organizations, organizational leaders need to understand some of the causes that facilitate such negative organizational behaviors to lessen the chances of unethical behaviors from occurring. In an effort to understand some of the causes of unethical behavior, this study looks at competitive atmosphere and results-focused performance evaluation as some of the influencing factors on employees' tendency to decide to behave unethically. Competition culture can spur unethical behavior and evaluation culture with emphasis on results-focused which can create a perception among employees of a narrow view of work and how it is defined. The argument of this paper is that such characteristics can create environment for unethical behaviors and serve as an added push upon employees to choose to behave unethically. Collection of survey results from those working in Busan area were used to test the hypotheses using regression. Data analysis showed that in organizational atmosphere that is overly competitive and results-focused can influence employees to behave unethically. Implications and future research suggestions are discussed in conclusions.

• Journal of the Korea Convergence Society
• /
• v.10 no.10
• /
• pp.161-171
• /
• 2019

This study aims the meta analysis based on the results of the empirical studies related to Job of life-long educators who are working in life-long education center, and the relationship between variables. In order to deliver this objective, articles published in domestic journals from December 2000 to April 2019 were collected, and total of 14 studies and 170 sub data were coded. With those data, the meta-analysis was executed by CMA(Comprehensive Meta Analysis) 3.0 program. The results of this meta-analysis study are as follows. First, the overall effect size associated with Job of life-long educators was 0.767, indicating between medium and large effect size. Second, the effect sizes of dependent variables that are influenced by job of life-long educators were Organization immersion, Job performance, Job satisfaction, and Job stress in order. Third, the effect size of Individual focus variables study was almost twice as big as that of mutual relation focus variables. The implications of this study were suggested based on the analysis results to provide the directivity about how we consider life-long educators related to their job.

• The Journal of the Korea Contents Association
• /
• v.19 no.9
• /
• pp.57-66
• /
• 2019

This study investigates the factors influencing to users' intention to retain monthly movie subscription VOD service in the Pay-TV. A dual model of a dedication-based mechanism and constraint-based mechanism used as the analytical framework for the service subscription retention. This study surveyed the total of 366 respondents who aged 15 years or older among the subscribers who use monthly movie subscription VOD service in Pay-TV from May 8 to May 14, 2018 through online surveys. And the study used SPSS 25 and AMOS 21 for data analysis. The results of the analysis are as follows. First, the price, the contents diversity and the ease of use were found to affect the user satisfaction. From three components, the price is the most effective and the ease of use is the next. Second, user satisfaction were found to affect the intention to retain a subscription in the dedication-based mechanism. Third, procedural switching cost were found to affect the intention to retain a subscription in the constraint-base mechanism.

• Management & Information Systems Review
• /
• v.38 no.1
• /
• pp.103-120
• /
• 2019

Recently, as mobile banking enables to instantly provide the customized service in accordance with customer demand via information technology. With this individual customized service, mobile banking plays a role of transforming the existing offline banking strategies. However, contrary to expectation, the mobile banking service has not been widely used to the extent that it can replace offline banking service. Therefore, the current study aims to explore the antecedents to affect customer's usage of mobile banking. Specifically, the antecedents influencing the intention to use and actual usage of mobile banking include personal-innovation fit, positive psychological capital, and service quality factors, which reflect the innovative technology characteristics of mobile banking. Furthermore, the paper also analyzes the effect of mobile banking service on intention to use and actual usage of mobile banking service. With empirical analysis using Structural Equation Modeling for 195 mobile banking users, the results showed that user's ability fit, value fit, and positive psychological capital positively affected user's future intention to use and actual usage of mobile banking. Furthermore, the current paper also found the significant moderation effect of usage purpose of mobile banking (banking task and online stock exchange) in the relationship between positive psychological capital and intention to use. This study suggests that banks need to develop mobile banking services that reflect customer's IT usability as well as their pursuing purpose and value.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.3
• /
• pp.320-333
• /
• 2019

Objective: The Shanghai Holstein cattle breed is susceptible to severe mastitis and other diseases due to the hot weather and long-term humidity in Shanghai, which is the main distribution centre for providing Holstein semen to various farms throughout China. Our objective was to determine the genetic mechanisms influencing economically important traits, especially diseases that have huge impact on the yield and quality of milk as well as reproduction. Methods: In our study, we detected the structural variations of 1,092 Shanghai Holstein cows by using next-generation sequencing. We used the DELLY software to identify deletions and insertions, cn.MOPS to identify copy-number variants (CNVs). Furthermore, we annotated these structural variations using different bioinformatics tools, such as gene ontology, cattle quantitative trait locus (QTL) database and ingenuity pathway analysis (IPA). Results: The average number of high-quality reads was 3,046,279. After filtering, a total of 16,831 deletions, 12,735 insertions and 490 CNVs were identified. The annotation results showed that these mapped genes were significantly enriched for specific biological functions, such as disease and reproduction. In addition, the enrichment results based on the cattle QTL database showed that the number of variants related to milk and reproduction was higher than the number of variants related to other traits. IPA core analysis found that the structural variations were related to reproduction, lipid metabolism, and inflammation. According to the functional analysis, structural variations were important factors affecting the variation of different traits in Shanghai Holstein cattle. Our results provide meaningful information about structural variations, which may be useful in future assessments of the associations between variations and important phenotypes in Shanghai Holstein cattle. Conclusion: Structural variations identified in this study were extremely different from those of previous studies. Many structural variations were found to be associated with mastitis and reproductive system diseases; these results are in accordance with the characteristics of the environment that Shanghai Holstein cattle experience.

• The Mathematical Education
• /
• v.58 no.1
• /
• pp.101-120
• /
• 2019

The goal of this study was to apply an expectancy-value model(Wigfield & Eccles, 2000) to explain changes in six multi-ethnic students' achievement motivation in mathematics during sixth (2012) to eighth (2014) grades. In order to achieve this goal, we used narrative research methods. Although individual students' achievement motivation and mathematics related life experiences differed, there are some common factors influencing their motivation development, especially (a) roles played by parents and teachers; (b) assessment of peers' competencies; (c) past learning experiences related to mathematics curriculum; (d) perception of the relationship between mathematics competency and other subjects; (e) home backgrounds; and (f) perceived task values. In this study, we achieved some insight into why some multi-ethnic students are willing to study hard to get good scores while others are uninterested in mathematics, and why some multi-ethnic students are likely to pursue new mathematical tasks and persist despite challenges, while others easily give up studying mathematics in the face of adversity. We argue that in order to increase and sustain multi-ethnic students' achievement motivation, educators and parents should recognize that motivation is contextually formulated in the intersection of current people, time, and space, not a personal entity formed in an individual's mind. The findings of this study shed light on the development of achievement motivation and can inform efforts to develop multi-ethnic students' positive motivation, which might influence their mathematics achievement and success in school.

• Journal of The Korean Society For Urban Railway
• /
• v.6 no.4
• /
• pp.327-337
• /
• 2018

Since the track of the ballastless steel plate girder bridge is connected to a main girder without a deck and a ballast, the impact generated by train passage is transferred directly to bridge main members, and it can cause frequent damage of the bridge as well as higher noise and vibration level. Applying the CWR (Continuously Welded Rail) technology can reduce this structural problems, and, to this end, it is necessary to understand the characteristics of factors influencing vehicle-track or track-bridge interaction. In this paper, experimental study results are presented for examining the longitudinal resistance characteristics of the track, including a rail fastener, a sleeper fastener, and a track skeleton, installed on a ballastless steel plate girder bridge. The experiment is conducted using a disposed bridge from service, which is transported to a laboratory. The experimental results show that the rail fastener satisfies the performance criteria of the longitudinal resistance presented in KRS TR 0014-15, and the longitudinal resistance of old and new type sleeper fasteners is higher than the values provided in the existing research. Also, the unloaded longitudinal resistance of the ballastless track is between the ballast and the concrete tracks.