• Korean Journal of Construction Engineering and Management
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• v.7 no.2 s.30
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• pp.171-180
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• 2006

Change is inevitable and is a reality of construction projects. Most construction contracts include change clauses and allowing contractors an equitable adjustment to the contract price and duration caused by change. However, the actions of a contractor can cause a loss of productivity and furthermore can result in disruption of the whole project because of a cumulative or ripple effect. Because of its complicated nature, it becomes a complex issue to determine the cumulative impact (ripple effect) caused by single or multiple change orders. Furthermore, owners and contractors do not always agree on the adjusted contract price for the cumulative impact of the changes. A number of studies have attempted to quantify the impact of change orders on project costs and schedule. Many of these attempted to develop regression models to quantify the loss. However, regression analysis has shortcomings in dealing with many qualitative or noisy input data. This study develops ANN models to classify and quantify the labor productivity losses that are caused by the cumulative impact of change orders. The results show that ANN models give significantly improved performance compared to traditional statistical models.

• Korean Journal of Occupational Health Nursing
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• v.27 no.2
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• pp.121-130
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• 2018

Purpose: The purpose of this study was to investigate the effects of major health issues and job stress on presenteeism among clinical nurses. Methods: The investigator conducted a survey on 226 clinical nurses at a general hospital in Seoul from March 3 to April 15, 2017, and analyzed their responses. Results: The findings showed that job stress did not have a significant effect on the nurses' presenteeism. Fatigue (t=3.55,p<.001) impacted job loss, one of the subcategories of presenteeism, with an explanatory power of 12.1%. Premenstrual syndrome (t=-2.67,p=.008) and fatigue (t=-2.46,p=.015) affected perceived productivity with an explanatory power of 23.6%. Conclusion: Based on these findings, the study highlighted the need for effective management programs to tackle fatigue and premenstrual syndrome among clinical nurses' major health issues in order to reduce their productivity loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1263-1270
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• 2012

Livestock disease that decreases the farm productivity and income leads to not only financial loss but also national loss from the spread of contagious disease. The purpose of this paper is to propose a livestock disease forecasting system that can diagnose disease of livestock at an early stage based on the livestock activity and body temperature. The proposed livestock disease forecasting system collect data on livestock activity and body temperature using a acceleration sensor and thermal imaging camera and comparing the data with control according to disease. It is expected that, this system can be accurately identify and prevent spread of livestock disease beforehand to minimize damages caused by disease to improve the productivity and the rate of return of livestock farms.

• Food Science of Animal Resources
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• v.21 no.1
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• pp.24-31
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• 2001

The effects of addition of activated carbon to diet of broiler on productivity and meat quality of broilers were investigated. 48 broiler raised for six week. The addition level of activated carbon to each group was added 0, 0.6, 0.9 and 1.2%, respectively. During the experimental feeding period, weekly gain and feed intake of treatment fed diets contain 0.6 and 0.9 percent activated carbon were higher compared with those fed on control diet, though effects of diets containing graded levels of activated carbon on the feed efficiency were not found. When broilers were fed activated carbon on crude protein level of birds were higher compared with that of control diet. Also, crude fat of broilers fed diet containing activated carbon were shown to decrease compared with those fed of control diet(p<0.05). The pH from activated carbon diets was rather higher than that of control(p<0.05). The content of VBN and TBARS was not significantly different among all treatments. The heating loss has tend to decrease in activated carbon diet groups(p<0.05). The WHC tend to be increase in activated carbon diet groups(p<0.05). Blood cholesterol was no significantly different.

• Safety and Health at Work
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• v.8 no.1
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• pp.99-104
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• 2017

Background: Workers laboring in steel industries in tropical settings with high ambient temperatures are subjected to thermally stressful environments that can create well-known risks of heat-related illnesses and limit workers' productivity. Methods: A cross-sectional study undertaken in a steel industry in a city nicknamed "Steel City" in Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration from urine color and urine specific gravity. A structured questionnaire captured self-reported heat-related health symptoms of workers. Results: Some 90% WBGT measurements were higher than recommended threshold limit values ($27.2-41.7^{\circ}C$) for heavy and moderate workloads and radiational heat from processes were very high in blooming-mill/coke-oven ($67.6^{\circ}C$ globe temperature). Widespread heat-related health concerns were prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures ($x^2=26.1258$, degrees of freedom = 1, p < 0.001). Change in urine color was 7.4 times higher among workers exposed to WBGTs above threshold limit values (TLVs). Conclusion: Preliminary evidence shows that high heat exposures and heavy workload adversely affect the workers' health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

• IE interfaces
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• v.18 no.1
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• pp.35-43
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• 2005

A production system in domestic shoes companies has difficulty in achieving automation and information because of insufficiency of flexibility and standardization. Particularly small and medium sized shoes companies producing by OEM have tendency to chase the given production schedule blindly without considering major factors that may affect the production. Therefore, the production schedules or the process conditions can not be optimally set and are extemporized by the experience in the past. These behaviors cause low productivity and financial loss. To maximize efficiency and productivity of the shoe-making process, we develop a simulation model based on a production system in small and medium sized shoes companies. The model has been developed using ARENA which has been demonstrated to be a powerful tool to simulate various manufacturing systems. Using the simulation model, we find out several problems for the production process, and then suggest several alternatives to improve the system.

• The Journal of Engineering Geology
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• v.9 no.2
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• pp.101-118
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• 1999

The pumping test analysis on 28 pumping test data in Duksan hot-spring area was performed using the fractal model, the leaky fractal model, and the steady-state dual-porosity fractal model. The fractional flow dimension 1.9 or 2.0 was determined in the central put of the hot spring and the fractional flow dimension 1.5-1.7 in the marginal area. For the flow dimension 2.0, the correlation between the transmissivity and the productivity index by the aquifer loss was much better than that between the transmissivity and the specific yield by the total drawdown. On the other hand, for the flow dimension 1.9, the correlation between the generalized transmissivity and the productivity index was very similar to that between the generalized transmissivity and the specific yield.

• Journal of Environmental Science International
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• v.28 no.10
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• pp.887-898
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• 2019

Rehabilitation work is required to increase well productivity, which decreases with the elapsed time of pumping owing to the clogging of the water well. Clogging causes not only a reduction in the well productivity but also a deterioration of the water quality. For unclogging and rehabilitating wells, several techniques are used such as brushing, air surging, surge blocks, and gas impulse. In this study, the high-pressure air impulse technique, which effectively and economically rehabilitates wells, was applied to a riverbank filtration site in Korea for the same objective. At most of the wells, the hydraulic parameters (transmissivity, storage coefficient, and specific capacity) were increased by the application of the high-pressure air impulse technique. The well loss change values also indicate an increase in the hydraulic parameters by the air impulse implementation. Thus, the high-pressure air impulse technique can be efficiently and economically applied to water and riverbank filtration wells for rehabilitating the decreased productivity.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.3
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• pp.1-14
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• 2022

Background : Tinnitus is common disorder with many possible causes and a symptom of many different diseases but has no effective treatment. Most of tinnitus patients experience the disorder to a degree that their quality of life and productivity are impaired. Especially tinnitus accompanied hearing loss causes severe discomfort in patients. Objectives : 1. Through symptoms of tinnitus, we tried to find out the relationship of Heo-sil(虛實) and Zuang fu bian zheng(臟腑辨證) among tinnitus patients accompanied Hearing Loss. 2. By testing THI, we tried to evaluate the quality of life of tinnitus patients group and tried to compare the quality of life between high-narrow tone and low-wide tone tinnitus patients group. 3. In the future, this study was planned to help monitor the prognosis and determine the progress of treatment for tinnitus patients who also have hearing loss. Methods : 43 patients were recruited in this study who was ill with tinnitus accompanied hearing loss. They wrote out the questionnaire about tinnitus and the Tinnitus Handicap Inventory(THI). Results : 1. In tinnitus patients, there were more men than women accompanied hearing loss. The rate of visits was higher as the age increased. 2. Most of the patients who visited the hospital had sensitive hearing loss. 3. In high-narrow tone tinnitus group, phlegm fire congesting-type are more uncomfortable than spleen-stomach weakness-type. 4. In low-wide tone tinnitus group, liver qi depression was the most uncomfortable. Conclusions : The present study suggests that tinnitus pattern may be helpful in differentiating patients with tinnitus, and the effectiveness of treatment can be predicted through differentiation. Zuang fu bian zheng(臟腑辨證) and Distinguishing between Heo(虛) and Sil(實) is expected to have positive effects on tinnitus accompanied hearing loss treatment.

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.18-21
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• 1996

A continuous production of fructooligosaccharides from sucrose was investigated by fructosyltransferase immobilized on a high porous resin, Diaion HPA25. The optimum pH(5.5) and temperature(55$^{\circ}C$) of the enzyme for activity was unaltered by immobilization, and the immobilized enzyme became less sensitive to the pH change. The optimal operation conditions of the immobilized enzyme column for maximizing the productivity were as follows: 600g/L of sucrose feed concentration, flow rate of superficial space velocity 2.7h-1. When the enzyme column was run at 50$^{\circ}C$, about 8% loss of the initial activity of immobilized enzyme was observed after 30 days of continuous operation, during which high productivity of 1174g/L$.$h was achieved. The kinds of products obtained using the immobilized enzyme were almost the same as those using soluble enzymes or free cells.