• Journal of Chest Surgery
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• v.31 no.9
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• pp.837-844
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• 1998

Background: Adenosine is secreted by myocardial cells during myocardial ischemia or hypoxia. It has many beneficial effects on arrhythmias, myocardial ischemia, and reperfusion ischemia. Although many investigators have demonstrated that cardioplegia that includes adenosine shows protective effects in myocardial ischemia or reperfusion injury, reports of the optimal dose of adenosine in cardioplegic solutions vary. We reported the results of beneficial effects of single dosage(0.75 mg/Kg/min) adenosine by use of self-made Langendorff system. But it is uncertain that dosage was optimal. The objective of this study is to determine the optimal dose of adenosine in cardioplegic solutions. Material and Method: We used a self-made Langendorff system to evaluate the myocardial protective effect. Isolated rat hearts were subjected to 90 minutes of deep hypothermic arrest(15$^{\circ}C$) with modified St. Thomas' Hospital cardioplegia including adenosine. Myocardial adenosine levels were augmented during ischemia by providing exogenous adenosine in the cardioplegia. Three groups of hearts were studied: (1) group 1 (n=10) : adenosine - 0.5 mg/Kg/min, (2) group 2(n=10): adenosine -0.75 mg/Kg/min, (3) group 3 (n=10) : adenosine -1 mg/Kg/min. Result: Group 3 resulted in a significantly rapid arrest time of the heart beat(p<0.05) but significantly slow recovery time of the heart beat after reperfusion(p<0.05) compared to groups 1 and 2. Group 2 showed a better percentage of recovery(p<0.05) in systolic aortic pressure, aortic overflow volume, coronary flow volume, and cardiac output compared to groups 1 and 3. Group 1 showed a a better percentage of recovery(p<0.05) in the heart rate compared to the others. In biochemical study of drained reperfusates, CPK and lactic acid levels did not show significant differences in all of the groups. Conclusion: We concluded that group 2 [adenosine(0.75 mg/Kg/min) added to cardioplegia] has better recovery effects after reperfusion in myocardial ischemia and is the most appropriate dosage compared to group 1 and 3.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.151-155
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• 2020

This study was conducted to determine the effects of the selection of an appropriate sowing method in on ginseng growth, and the results are as follows. SAS (semi-automatic sower), commonly used by direct seeding farms, provides fast operation speed but results in high labor cost, while (Hooper Seeder Sowing) offers fast operation speed and high germination rate, but leads to increased laborer's fatigue. Daily working area per sower was 6,611 ㎡ for a motor type, and the operation time to sow 3,305 ㎡ was 15 hours for broadcast planting, and 8 hours for SAS. The germination rate of 1-year-old ginseng according to direct seeding was 69.1% for the treatment plot under broadcast planting, followed by 66.4% and 67.3% for manual sower and hoop sower, respectively, and the germination rate of SAS was the lowest at 64.2%. In addition, there were no differences in shoot and root growth of 1-year-old ginseng among the sowing methods. Therefore, the sowing method can be chosen depending on the economic size of ginseng farmers. That broadcast sowing (BS) is appropriate for small scale farmers, while motor-driven seeder sowing (MDS) for direct seeding is more suitable for large scale farmers.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.109-118
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• 2007

This study was conducted to provide the fundamental data of the policy plan for the security of forestry labour and the revitalization of forestry mechanization by analysing the status of forestry labor and the training plan. In forestry, the total number of employer and the labour cost have slightly increased annually, but the number of employer for timber harvesting has decreased. Therefore, the organization of expert forestry mechanization unit and the training of operator will be necessary. The number and person of forest management unit, the working days of the year and income have increased in Korea. However, the working days per month of forest management unit were only 15 days, which are only 180 days per year. In the results of the calculated number and person of forest management unit for the Korean forest tending volumes, about 349 forest management units are required. In case of adjusting 12 persons per 1 unit, 4,185 persons are required. In calculated results of the optimum forestry mechanization unit and member's number by the adjusting of tower yarder harvesting system for annual timber harvesting production volume, it was known to necessary the 250 forestry mechanization unit and the 1,250 members which are calculated at 5 persons per 1 group.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.249-263
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• 2004

Objectives: The objectives of the present study were to establish the exposure monitoring method of chlorpyrifos and chlorothalonil application to pear and field red pepper by vehicle-mounted sprayer, hand-held sprayer and to assess the risk. Methods and Results: Chlorpyrifos met all of requirements of sampling and analysis method(U.S. EPA), but chlorothalonil met only dermal patch method. Potential dermal and inhalation exposure was evaluated in 42 farmers. Compared with the hand-held sprayer application, vehicle mounted sprayer demonstrated producing relatively lower dermal exposure levels with statistical significance. In dermal exposure during hand-held application, there is no significant difference between pear and red pepper. Conclusions: This results show that application method is the main factor of dermal exposure. There was no statistically significant difference between each group of respiratory exposure level. The margin of safety (MOS) was calculated to assess the risk of pesticide exposure. All Chlorpyrifos MOS values are lower than 0.2, which mean working conditions are unsafe. In order to protect farmers, big efforts to control exposure are needed.

• Journal of Korea Port Economic Association
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• v.30 no.4
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• pp.47-67
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• 2014

This study examined elements which could evaluate a container terminal logistics system from the viewpoint of supply chain management. This study derived the elements of a container terminal logistics system such as flexibility, reliability, responsiveness, and information sharing and 16 evaluation sub-items in the aspect of a supply chain. In the result of analysis, the weight between SCM elements of a container terminal logistics system was the highest in reliability(0.282), followed by flexibility(0.273), responsiveness(0.224), and information sharing(0.221). The conversion weight was calculated by combining the weight of elements of a container terminal logistics system and the weight of evaluation sub-items. The highest weight which was considered as the most important factor to evaluate a container terminal logistics system was work planning(berth, yard) of flexibility(0.081), followed by accurate fulfillment of container work schedule(ship, yard) and the optimum distribution and arrangement of equipment(QC, TC, YT)(0.079), stable works without damage of containers and ships(0.071), and preventive maintenance of equipment and operators' skill(0.070).

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.93-108
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• 2023

In manufacturing productivity analysis, understanding the intricate interplay among factors like facility performance, layout design, and workforce allocation within the production line is imperative. This paper introduces a simulation-based methodology tailored to food manufacturing, progressively expanding scenarios to analyze production enhancement. The target system is a food processing plant, encompassing production processes, including warehousing, processing, subdivision, packaging, inspection, loading, and storage. First, we analyze the target system and design a simulation model according to the actual layout arrangement of equipment and workers. Then, we validate the developed model reflecting the real data obtained from the target system, such as the workers' working time and the equipment's processing time. The proposed model aims to identify optimal factor values for productivity gains through incremental scenario comparisons. To this end, three stages of simulation experiments were conducted by extending the equipment and worker models of the subdivision and packaging processes. The simulation experiments have shown that productivity depends on the placement of skilled workers and the performance of the packaging machine. The proposed method in this study will offer combinations of factors for the specific production requirements and support optimal decision-making in the real-world field.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.212-219
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• 2003

In construction project planning and control, a cost model performs a critical role such as cost determination on a contract stage and cost tracing. The model can maximize owner's profit and value within the project budget and optimize cost management works on overall construction implementation stages. A BoQ(Bill of Quantities) generally adopted in a unit price contract has been applied as an important tool for cost control and forecast. However a previous cost model based on the BoQ has shown limitations in that it requires too detailed information and heavy manpower on cost management and difficulty in keeping relationship with construction planning, scheduling and progress management. The each cost items and unit prices which constitute of construction works are individually very important management factors but the relative weight for each items and prices have a difference on the contents and conditions of each conditions of each construction works. In consideration of this structural mechanism of cost determination, this research is aimed at examining the critical factors affecting the construction cost determination and propose and verify a new cost forecasting model which is more simple and efficient and also keeps the accuracy of cost management.

• Resources Recycling
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• v.21 no.6
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• pp.23-31
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• 2012

Removal work about weeds that grow naturally on road and industrial complex is attaining ordinary times but is suffering difficulty in weeding work by strong self-generation power. In the meantime, going side by side with these manual processing and weeding work through construction of weed-proof seat is attaining, but economic performance, limitation of application region and withdrawal processing problem are being blamed for shortcoming. The scope of this study is about the manufacture of weed-proof mortar using eco-friendly industrial byproducts characterized by an economic and simplicity for not limited to loss of function as a product recovered after treatment. After the carried out the various experiments and actual construction for the selection of mixing materials and derivation of appropriate mix, through the comparison and analysis of results, it was investigated the research results of weed-proof mortar for fundamental development.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.247-253
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• 1982

This experiment was conducted to find out the optimum date for Combine harvesting of barley in the double cropping paddy field. By the consideration of moisture contents of grain, grain loss, rate of unhulled grain, and discoloring of external plant parts, the optimum date for harvesting was observed to be about 41 days after heading under natural condition. On the other hand, when desiccant was applied on the 34 days after heading, it could be shortened natural harvesting time for 3 days without any yield loss and grain qualities, too.

• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.175-183
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• 2019

The purpose of this study is to present the basic information about advancement of computer network system for colleges that are preparing or in progressing upgrading. For this, we investigated the necessity and direction of computer network system upgrading work, basic guidelines, development requirements, and construction environment. And we suggested those informations through the main subject. In conclusion, we propose that we can obtain expected results such as efficiency improvement of administrative work, strengthen competitiveness, ensure inter-work connectivity, increase the efficiency of student management, efficient workforce placement, provide integrated centralized control solution and building smart campus through computer network system upgrading project.