• Safety and Health at Work
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• v.3 no.4
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• pp.268-277
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• 2012

Objectives: 1) To determine mercury levels in urine samples from garbage workers in Southern Thailand, and 2) to describe the association between work characteristics, work positions, behavioral factors, and acute symptoms; and levels of mercury in urine samples. Methods: A case-control study was conducted by interviewing 60 workers in 5 hazardous-waste-management factories, and 60 matched non-exposed persons living in the same area of Southern Thailand. Urine samples were collected to determine mercury levels by cold-vapor atomic absorption spectrometer mercury analyzer. Results: The hazardous-waste workers' urinary mercury levels (10.07 ${\mu}g/g$ creatinine) were significantly higher than the control group (1.33 ${\mu}g/g$ creatinine) (p < 0.001). Work position, duration of work, personal protective equipment (PPE), and personal hygiene, were significantly associated with urinary mercury level (p < 0.001). The workers developed acute symptoms - of head-aches, nausea, chest tightness, fatigue, and loss of consciousness at least once a week - and those who developed symptoms had significantly higher urinary mercury levels than those who did not, at p < 0.05. A multiple regression model was constructed. Significant predictors of urinary mercury levels included hours worked per day, days worked per week, duration of work (years), work position, use of PPE (mask, trousers, and gloves), and personal hygiene behavior (ate snacks or drank water at work, washed hands before lunch, and washed hands after work). Conclusion: Changing garbage workers' hygiene habits can reduce urinary mercury levels. Personal hygiene is important, and should be stressed in education programs. Employers should institute engineering controls to reduce urinary mercury levels among garbage workers.

• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.93-107
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• 2000

The excessive exposure to powered hand tools can cause damage to nerves, impair blood circulation, and musculoskeletal damage. The symptoms associated with hand-arm vibration syndrome (HAVS) include numbness, tingling, pain and subsequent reduced dexterity of the hands. This study was performed to report the prevalence of the HAVS and evaluate its related factors among the workers using powered hand tools. Total 282 workers in 11 plants of Kyungki and Inchon areas were examined. A standard symptom questionnaire was developed and administered to collect information on personal characteristics, work history, operating conditions, tool characteristics, and subjective symptoms of HAVS. Mean values (standard deviations) of the age, the duration of powered hand tools used, and the daily hours using powered hand tools were 38.3(8.9) years, 79.3(62.2) months and 6.0(2.6) hours, respectively. 132 workers(46.8%) showed vibration-induced white finger symptoms according to the Taylor-Pelmear classification, and 30 workers(10.6%) were interfered with the work. The results of a multiple logistic regression analysis controlling for age and daily working hours showed that smoking, work duration, weight of tools, and continuous work over 2 hours were significantly associated with the symptom of HAVS.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.49-56
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• 2010

A competitive construction project must address factors such as cost, performance, aesthetics, schedule and quality. The importance of these factors will vary from project to project and from market to market. Productivity is becoming an ever-more important factor in the acquisition of a project. As the technology or aesthetics of a product matures or stabilizes, and the competitive playing field levels, competition is increasingly based on time. Recently, the construction industry has been depressed due to difficult market circumstances. At this time in particular, construction companies are striving to rationalize their management, both in their planning offices and in the field. In this study, we present a method of calculating a reasonable duration for reinforced form work. We did this by first developing a question for field workers, then sampling form workers based the question. Second, we employed a work analysis method to analyze worker"s work-methods and Time. Then, using the result of this analysis, we measured the Productivity of form work. This measure can be used as basic data to determine the appropriate duration of form work.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.63-68
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• 2002

This study performed to evaluated musculoskeletal disorders(MSDs) during sitting work. The musculskeletal system is affected by various work factors such as strength, weight, posture, repetition, duration and exertion. Ergonomic study on sitting work is necessary to evaluate these factors affecting human body. But the strength and work load data by the work factors are insufficient in Korea. Therefore, this study evaluated the work load using the elcctromyogram(EMG) and measured the arm strength by arm posture and push pull work during sitting work. to evaluated muscle load, the vertical height and horizontal angle of arm were adjusted around acromion. And EMG data were recorded on pc during the test.

• Safety and Health at Work
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• v.13 no.2
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• pp.135-140
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• 2022

Background: Coal mining is a hazardous industry. The purpose of the study is to identify the nature of occupational injuries and diseases among coal miners and to determine the factors that affect the rate of injury and duration of time loss from work. Methods: A retrospective cohort study was conducted using accepted workers' compensation claims data of 30,390 Australian coal miners between July 2003 and June 2017. Results: Musculoskeletal and fracture conditions accounted for approximately 60% of claims in all occupational groups. Cox regression analysis showed that older age and female gender were significant predictors of longer time off work. Injury types and occupations were associated with work time loss: mental health conditions, and machine operators and drivers had significantly longer durations of time off work. Conclusion: Future research can further address how these factors led to longer time off work so that coal industry regulators, employers, and healthcare providers can target interventions more effectively to these at-risk workers.

• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.255-259
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• 2010

In this work, Ni-Co composites incorporated with nano-sized SiC particles in the range of 45-55 nm are prepared by electroplating. The effects of plating duration on the chemical composition, surface morphology, crystalline structures and hardness have been studied. The maximum hardness of Ni-Co-SiC composite coating is approximately 633 Hv at plating duration of 1 h. The hardness is gradually decreased with increasing plating duration, which can be attributed to the growth of crystalline size and the agglomerates of SiC nano-particles. It is therefore explained that the grain refinement of Ni-Co matrix and stable dispersion of SiC particles play an important role for strengthening, which indicate Hall-Petch relation and Orowan model were dominant for hardening of Ni-Co-SiC composite coatings.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2155-2156
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• 2006

The purpose of this work is to investigate the fundamental properties of the gradual muscle force potentiation for the prediction of muscle force and body movement from the stimulation input with musculo-skeletal model. We investigated the dependence of force potentiation on both the pulse-amplitude and the pulse-duration. The experimental result showed that the force increment ratio during electrical stimulation decreased with pulse-amplitude. The force increment ratio decreased with short pulse-duration and was maintained to be constant with pulse-duration longer than $500{\mu}s$. A new model of the muscle potentiation based on these results is desired in the future.

• Phonetics and Speech Sciences
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• v.7 no.4
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• pp.103-110
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• 2015

The purpose of this study is to assess the vowel property by examining the vowel duration of the American English vowles found in the Buckeye corpus[6]. The vowel durations were analyzed in terms of various linguistic factors including the number of syllables of the word containing the vowel, the location of the vowel in a word, types of stress, function versus content word, the word frequency in the corpus and the speech rate calculated from the three consecutive words. The findings from this work agreed mostly with those from earlier studies, but with some exceptions. The relationship between the speech rate and the vowel duration proved non-linear.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.10
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• pp.458-463
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• 2006

The purpose of this work is to investigate the fundamental properties of the gradual muscle force potentiation. We investigated the dependence of force potentiation on both the pulse-amplitude and the pulse-duration with different ramp-up time. The experimental results showed that the force increment ratio (FIR) during constant electrical stimulation decreased with pulse-amplitude and also with pulse-duration. The FIR was greater with short ramp-up time in both the pulse-amplitude and pulse-width modulation. The feasible mechanism might be that the myosin light chain phosphorylation induces the force potentiation and it occurs only in the fast type muscle fibers which are recruited first. These observations indicate that muscle potentiation must be understood well for the accurate control of muscle force.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.111-119
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• 2007

Firemen are directly exposed to various harmful chemicals, physical factors and mental stress during rescue and fire-fighting. In fire extinguishing, unstable posture, poisonous gas, dust, high temperature and heavy equipments are possible hazardous factors. The alertness for emergency, shift work, job strain and stress are also possibly hazardous. Therefore, this study aimed to investigate the prevalence of musculo-skeletal symptoms and job stress and to determine risk factors in firemen. This study was carried out in a group of 226 firemen in Busan City, Korea. Standardized Nordic Questionnaire was used to investigate the prevalence of musculo-skeletal symptoms and Psycho-social Well-being Index (abbreviated PWI) was used to investigate the prevalence of job stress. General and occupational characteristics were included education, marital status, alcohol and smoking history, working duration, and work shift system. Body mass index (BMI) scores were calculated by physical examination including height and weight. Concerning musculo-skeletal complaints, the commonest site was neck, and shoulder, lower back, upper back were the next. Complaint site above one area of body was about 80%. From multiple logistic regression analysis, working duration was significant variable in musculo-skeletal symptoms. Odds ratio were 15.4 in working duration. About 16.8% was high risk stress group. From multiple logistic regression analysis, shift work and alcohol drinking were significant variables in PWI scores. Odds ratios were 2.25 in shift work. Accordingly, interventions are needed for health promotion of long term and shift worker.