• Fire Science and Engineering
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• v.29 no.1
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• pp.73-79
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• 2015

There are three kinds of design method of the fire sprinkler systems. Grid type is connected all branch as a trapezoid. Loop type is connected cross-mains like circle. The last one is a tree type most commonly used. Grid type needs computer program to calculate the friction loss and flow rate apart from very simple form. In loop type, manual calculation is possible. Design engineer can draw up and calculate the demands without computer program. Because water supplies two direction in loop type, friction loss is smaller than tree type. Water distribution in operation area is uniform because of the small differences of sprinklers discharge pressure. Loop type is superior to tree type in respect of total pressure and flow rate. Using the small diameter pipe, the labor and construction cost will be decreased in the end. Loop type sprinkler design is rarely laid out because design engineers don't know the method. This paper is intended to inform that the loop type is better than the tree type in performance and economic point of view. And also this paper intend to use the loop type easily and widely.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.75-84
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• 2018

In this study, the researchers attempted to automate the process of painting the characters on the road surface, which is currently done by manual labor, by using the information and communication technology. Here are the descriptions of how we put in our efforts to achieve such a goal. First, we familiarized ourselves with the current regulations about painting letters or characters on the road, with reference to Road Mark Installation Management Manual of the National Police Agency. Regarding the graphemes, we adopted a new one using connection components, in Gothic print characters which was within the range of acceptance according to the aforementioned manual. We also made it possible for the automated program to recognize the graphemes by means of the feature dots of the isolated dots, end dots, 2-line gathering dots, and gathering dots of 3 lines or more. Regarding the database, we built graphemes database for plotting information, classified the characters by means of the arrangement information of the graphemes and the layers that the graphemes form within the characters, and last but not least, made the character shape information database for character plotting by using such data. We measured the layers and the arrangement information of the graphemes consisting the characters by using the information of: 1) the information of the position of the center of gravity, and 2) the information of the graphemes that was acquired through vertical exploration from the center of gravity in each grapheme. We identified and compared the group to which each character of the database belonged, and recognized the characters through the use of the information gathered using this method. We analyzed the input characters using the aforementioned analysis method and database, and then converted into plotting information. It was shown that the plotting was performed after the correction.

• Journal of Korean Society of Disaster and Security
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• v.14 no.3
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• pp.39-49
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• 2021

According to the recent "Status of Industrial Accidents at the End of December 2020" released by the Ministry of Employment and Labor, each industry is subject to industrial accidents. The number of accident deaths by construction industry, accident deaths by accident type fell, and accident deaths by workplace size were 5 to 49, indicating that most accident deaths occurred due to falling accidents at small construction sites. Therefore, urban living houses are small construction sites, and the probability of falling accidents is very high. Fall simulation training for disaster occurrence is conducted mainly by large construction ordering organizations in the public sector, and it is the first case in Korea that a housing construction company has conducted at a small construction site. This study analyzed and presented the definition, construction characteristics, and safety management status of urban living houses, and developed and spread an emergency relief procedure manual in the event of a fall accident to minimize deaths.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.73-78
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• 2002

Cabbage is one of the most important vegetable in Korea. The cabbage production was mainly based on human labor A comprehensive research fur substituting the human labor by machines has been performed until now. In general, cabbage is cultivated on hillside in Korea. Picking up the harvested cabbages in field and carrying to a vehicle fur transportation are very laborious work. Manual transportation of cabbage is likely to damage the quality and is also a cause to increase the cost of cabbage production. This study was to develop and evaluate a prototype cabbage loader fur efficient and safe transportation of cabbage. The developed loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transportation and loading of cabbage in a steep field. The maximum loading weight of the loader was 1.0 ton. By using two sets of safety devices attached to the loader to avoid the roll-over in a steep field, the static rollover slopes were increased up to 34.0% and 37.4% fur the left and the rear direction, respectively The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The loading capacity of the loader was about 35 pallets/hr when picking up, carrying, and unloading two cabbage pallets for one loading operation. The loading capacity was more than 8 times in comparison with the conventional human labor. The developed loader could be used fur loading and carrying the other vegetables. The study suggested a possible approach for designing the field machines operated on hillside.

• Health Policy and Management
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• v.14 no.4
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• pp.1-20
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• 2004

This study is to examine relationships of several socioeconomic position indicators with mortality risk in a nationwide longitudinal study of South Korea. The Korea Labor & Income Panel Study, conducted on a probability sample of urban South Korean households by Korea Labor Institute, contains date of death information for the decedents which were used to estimate relative risks of mortality and their $95\%$ confidence intervals (CI) with Cox regression analysis. A total of 125 men and women among 8,415 subjects died between 1998 and 2002. Socioeconomic differentials in mortality were observed after adjustment for sex and age. Those with less than 12-year education had 1.90 times $(95\%\;CI=1.25-2.91)$ greater mortality risk than those with 12-year education or more. Greater mortality risks were also found among those with low occupational class and manual occupation. The magnitude of differentials in mortality risks between occupational class were similar in two different approaches to measuring women's occupational class: (1) approach 1 where women, married or not, retain their own occupational class, and (2) approach 2 where married women are assigned their husbands' occupational class. Relative risks of dying among those with low household Income were 1.62 $(95\%\; CI=1.08-2.42)$ compared with the counterparts. Those who reported economic hardship at the time of survey in 1998 had greater risk of mortality $(RR=1.83,\;95\%\;CI=1.21-2.78)$ than those who did not. In conclusion, increased social discourse and policy discussions about these health inequalities are needed in Korean society. Future studies should explore the causes and mechanisms of socioeconomic mortality inequalities.

• Journal of Forest and Environmental Science
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• v.19 no.1
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• pp.48-68
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• 2003

There have been some problems of high labor. low productivity in the existing systems of bonsai cultivation. This study was conducted to cultivate a large quantity of hig-quality bonsai through the development of bottom irrigation system and management method. Bonsai placed on the FRP bed were grown very well by bottom irrigation system compared with direct watering and sprinkler system. It was concluded that bottom irrigation system was possible to reduce considerable manual labor and produce mass production of high-quality bonsai within shorter periods. This research was finally found that the growth was significantly better and earlier production was certain in the vinyl house, had another advantage which could cultivate less cold-resistant species and therefore broadened a range of species selection for market supply. Cultivation techniques by the use of vinyl house and bottom irrigation system developed was quite effective for early production of bonsai as well as for high productive and value added. This project developed a new practical techniques and systems which can make mass and early production of bonsai with high quality through input of less labor. Interest in bonsai is now expanding in landscape horticulture and other fields concerned, and bonsai export of our country is also increasing. Results from this research will make a great contribution to enhancing of bonsai cultivator's competitive position in world markets and to improving of their annual income.

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.2
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• pp.79-89
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• 2023

This paper is about the development results of an automatic silkworm breeding system to reduce labor and time by automatically performing the works for silkworm droppings changing and feed its food. It consists of an automatic guided vehicle and a processing unit. The automatic guided vehicle transports a silkworm dropping changing frame mounted on a silkworm tray stand, and the processing unit takes over the dropping changing frame on it, removes excrement contained the droppings changing frame and feeds silkworm food. In the case of the current silkworm farming, because the breeding period for large silkworms (4 to 5 stage) is short to 14 days and the supply of mulberry leaves takes 98% of the total amount of mulberry leaves needed for breeding silkworms at this time, labor concentration is intensive, and all breeding works depends on manpower. Therefore, it was difficult to breed large silkworms on a large scale. Moreover, silkworms are bred by adding Silkworm bed (Seop) and mulberry in the silkworm tray, and their droppings changing is to separate silkworms and excrement by moving silkworm trays one by one, and the production cost increases due to the high-cost manpower for silkworm breeding. To solve this problem, technology for automating silkworm breeding has also been developed. However, there is still a limitation that silkworm feeding and droppings changing works are not suitable for mass breeding because a lot of labor and time are spent depending on manual work. Therefore, a new silkworm breeding system for breeding silkworm automatically is needed and so we developed an Automatic Silkworm Breeding System applying the droppings change frame, the inverting unit, the feeding silkworm food device and automatic guided vehicle.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.57-62
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• 2015

Manual grafting is a labor-intensive operation and highly susceptible to human error. Development of grafting robot has been considered as an effective alternative to manual grafting. The study was conducted to investigate the grafting efficiency between the domestically produced automated grafting robot and traditional manual grafting performed in a commercial plug seedling greenhouse. Plug seedlings of pepper (Capsicum annuum L.) 'Buchon' and 'Anseongmatchum' were sown as scions and rootstocks, respectively on March 29, 2013. The grafting was performed by a grafting robot, amateur grafters, and professional grafters on May 31, 2013. After grafting, the seedling efficiencies and seedling characteristics were compared in terms of plant height, the number of success as well as failure of seedling grafts produced in an hour. The results showed that plant heights were most uniform in the grafts performed by the professionals that had a 0.6 cm difference whereas an uneven difference of 2.1 cm difference was observed in plug seedling grafted by an amateur. However, plug seedlings grafted by the grafting robot were found to be uniform with 1 cm plant height difference. Moreover, the maximum number of grafting processed plug seedlings per hour (667 plants) was achieved by the grafting robot on compared with the seedlings grafted (466 plants) by the professionals. Furthermore, the least failure rate of 21.7% was noted upon the usage of grafting robot than the manual grafters. Thus, the results demonstrate that the technology of automated grafting robots is the most appealing and can be employed in commercial plug seedling greenhouses to overcome the drawbacks of manual grafting.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.565-574
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• 2019

In this study, we evaluated the usefulness of an automatic blood typing analyzer using QWALYS-2 up (Diagast, Loos Cedex, France). During a month( 01OCT2013 - 31OCT2013) we performed 1,636 tests for ABO & RhD blood typing, 1,374 tests for antibody screen & identification tests and compared the results by automatic blood type analyzer with previous manual methods and column agglutination tests. And we analyzed the economic performance by comparison the test unit price between automatic blood type analyzer and manual methods. In ABO & RhD blood typing tests, there were complete concordances between manual and automated blood typing analyzer for 200 clinical samples. In Antibody screen tests, the concordance rate between manual and automated blood typing analyzer was 98.5% and more strong reaction in automated blood typing analyzer than manual methods. Therefore, the introduction of an automated blood typing analyzer, reagents costs were increased but labor costs were decreased. Considering the importance of transfusion safety and economic advantages, the introduction of an automated blood typing analyzer was very useful.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.9
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• pp.1462-1469
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• 1997

This study presents a genetic algorithm-based method for optimizing control parameters in fluid power systems. Genetic algorithms are general-purpose optimization methods based on natural evolution and genetics. A genetic algorithm seeks control parameters maximizing a measure that evaluates system performance. Five control gains of the PID-PD cascade controller fr an electrohydraulic speed control system with a variable displacement hydraulic motor are optimized using a genetic algorithm in the experiment. Optimized gains are confirmed by inspecting the fitness distribution which represents system performance in gain spaces. It is shown that optimization of the five gains by manual tuning should be a task of great difficulty and that a genetic algorithm is an efficient scheme giving economy of time and in labor in optimizing control parameters of fluid power systems.