• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.50-57
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• 2017

This study investigated the causes and problems of train operation impediments through the statistics analysis of 8 years'internal data of Daejeon Metropolitan Express Transit. By evaluating the risks regarding the system, equipment, and parts of high risk group, this study measured the Risk Index Severity, and applied the $5{\times}5$ Risk Assessment Matrix which is a method of risk management to calculate the scale of risk to analyze the safety level and allowance range. As a result, the car sector, the most serious risk, followed by machinery and equipment sector showed that the inherent risk. In particular, the door broken and the door rail signaling and control devices due to defects of the vehicle is high, but also the severity, and frequency are showing very frequent additional potential accidents. PSD also had defects in the machinery sector appeared to be the most dangerous of the PSD poor safety gates, it was found that the glass also involve the risk of mishandling and breakage of the PSD. This study intended to contribute to the transportation benefits through the safety and stable operation of Metropolitan Express Transit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.246-253
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• 2018

The main industries in Chungcheongbuk-do are the smart IT parts; bio-health; and transportation machinery, materials and parts. The transportation, machinery, materials and parts (TMMP) industry is a key source technology for environmentally friendly and intelligent vehicles related to future vehicles in the machinery sector. Business support projects to improve this industry are currently underway. In this study, the number of enterprises, number of employees, amount of shipment, and added value of the enterprises in Chungbuk area were analyzed for the downstream and rear industries of the transportation, machinery, materials, and parts industry to set targets and directions for the technical support projects during the enterprise support. In particular, for the SMEs with less than 50 employees, the changes in the value added per enterprise were analyzed according to the period from the year of foundation. In the case of the rear industry, the value added by companies within three years after foundation has decreased gradually each year, so technical support is needed at the beginning of the startup. Companies between the ages of five and nine years are showing a fluctuating trend each year. Therefore, it is necessary to support business diversification or find new items.

• Journal of Biosystems Engineering
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• v.40 no.1
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• pp.19-27
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• 2015

Purpose: A system to measure the visibility of agricultural tractor operators was designed and evaluated according to ISO standards, and a blind area diagram around the tested tractor was created based on the manual method recommended by the National Institute for Occupational Safety and Health (NIOSH). Methods: A visibility measurement system was designed and evaluated based on the ISO 5006 and ISO 5721-1 standards. Two bulbs used to simulate the operator's eyes were mounted on a bar with a supporting frame. A wooden frame was used to determine the seat index point position. The 12-m visibility test circle was divided into six sectors of vision, and the test tractor was placed at the center of the circle. Artificial light was supplied in the darkened environment, and shadow or masking effects were measured manually around the 12-m circle. Results: When the bulbs were placed at the operator's eye level, front visibility was good; no masking was found in the "A" vision sector, but larger masking widths were found in the "B" and "C" vision sectors. Since the masking width exceeded 700 mm, additional tests, such as movement of the light sources to both sides of the operator's eye level, were performed. Less than six masking effects were found in the semi-circle of vision to the front, and more than one masking was found in the "B" and "C" visual fields. The minimum distance between the centers of two masking effects exceeded 2500 mm when measured as a chord on the semi-circle of vision. A blind area diagram was created to define the exact nature of the blind spots and mirror visibility. Conclusions: Visibility evaluation is an effective way to enable proper and safe operation for agricultural tractor operators. Inclusion of this visibility evaluation test in the general testing process might aid tractor manufacturers.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1013-1025
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• 1993

Agriculture in Swaziland is the most important sector of the economy from the stand point of export earning, rural employment and dependency for family food. But, inspite of 65.5 percent of the household being busy in food production for family consumption in Swaziland, the import bill of food and live animals is rising from E119.7268 million in 1987/90 (An.St.Bul.1988) . A typical farm size, based on holding's growing crops, is only 1.93 ha which may prohibit owning a four wheel tractor for farm operations. The traditional hand tools are just not efficient and comfortable to operate in order to exploit full potential of the land. There are over 120.000 draught animals which have potential to be utilized in farming. The two wheel-tractor is another energy source which can be used for many farm-operations.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.114-115
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• 2018

Since the introduction of the C.M(Construction Management)system in the Basic Law of the Construction Industry in 1997, the recent arrangement of construction management engineers in public sector buildings has generally been based on architecture·civilengineering·machinery·landscaping, electricity, telecommunication, fire fighting by the number of M/M(Man and Month). In the field of engineers arrangement in each field, the arrangement of M/M according to the workload of architecture.civilengineering.machinery.landscaping and electricity is inadequate causing conflicts and C.M among construction management engineers. Therefore, this study aims at basic research that is used to identify the problems through the questionnaire and to prepare future improvement plans.

• Journal of Korea Technology Innovation Society
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• v.16 no.2
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• pp.391-407
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• 2013

The paper tests the embodiment hypothesis by measuring the technological obsolescence of a specific year (1990)'s technology and investigating the relationship between labor productivity and technological obsolescence. This approach is based on Salter (1969) that emphasizes the economic aspect of technology. We use the rate of economic surplus as the proxy of technological obsolescence for 10 main industries, including food processing, textiles, chemicals, non-steel metals, steels, metal products, machinery, electronics, precision machinery, and transportation equipments. The result shows that the embodiment hypothesis is not accepted for the overall manufacturing sector. However, we found the vintage effect - a positive relationship between technological obsolescence and labor productivity over time - in textiles, chemicals, non-steel metals, metal products, electronics, and transportation equipments. Therefore, the government should support R&D investment as well as capital equipments investment for the industries with large vintage effect.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.44-53
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• 2021

As environmental issues have emerged worldwide, emission gas regulations have been strengthened. In the construction machinery sector, studies have been actively conducted to utilize the power source of electric motors owing to the increasing demand for zero emissions. In this study, the gear specifications of an electric axle for construction machinery were selected by considering the specifications of the motor, gear tooth contact pattern, and face load factor. The gear strength evaluation was performed at the system level using the simulation model. The bending and contact strength of the spiral bevel gears and the bending strength of the planetary gear set showed a safety factor of 1 or more. However, the contact strength of the planetary gear set showed a safety factor of 0.92. Conservative results were derived by performing the analysis under the rated load condition of the motor. However, the ratio of the equivalent torque to the rated torque of the motor was 45% or less, hence, it was determined that no difficulties should arise regarding the durability of the axle.

• Journal of the Korean Regional Science Association
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• v.11 no.1
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• pp.1-20
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• 1995

This paper studies the comparative advantage of competitive and specialized regional industries which are manufacturing, wholesale and retail trade, servies in the metropolitan area-Seoul, Inchun, Kyunggi-do of Korea, For the analysis of industries, the coefficient of specialization, the indices of competitiveness of labor and value-added, the growth rate are simultaneously examined under the criteria of the number of workers, value of shipment, value-added, This comperative synthetic analysis is different from the traditional approaches. This paper shows that the perfectly competitive advantage of specialized industries satisfying all of three criteria are 'other business related activities', 'recreational, cultural and sporting activities' in Seoul, 'machinery and outfits, n.e.c', 'retail trade, except of motor vehicles and motorcycles, repair of personal and household goods' in Inchun. We conclude that each should strategically develop the region-oriented specialized industry which has the comparative advantage. It is the reason why the concentration of industry in necessary for the leading of regional industry under the weaken local public finance. Moreover, such an industy should provide the increase of employment and income from the viewpoint of the activation of regional economy. The potential-specialized competitive industry requires the advanced structure of production under the criteria of value-added. For the development of the metropolitan area's economy, the highly advanced technology industry including computer and electronics should be induced through the loosening of metropolitan regulation. Research center(science park) supported by th private-public sector should be built for the increase of technology sector should be built for the increase of technology power of the small and medium enterprises, Also it is necessary that the small and medium enterprises strategically make the cooperative-large group in order to avoid the disadvantage from the size.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.2
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• pp.9-17
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• 1984

Laminar and turbulent boundary layers on a rotating sector and a helical blade are calculated by differential method. The estimation of three dimensional viscous flows provide quite useful informations for the design of propellers and turbo-machinery. A general method of calculation is presented in this paper. Calculated laminar boundary layer on a sector shows smooth development of flows from Blasius' solution at the leading edge to von Karman's solution of a rotating disk at the down-stream. Eddy viscosity model is adopted for the calculation of turbulent flows. Turbulent flows on a rotating blade show similar characters as laminar flows. But cross-flow angle of turbulent flows are reduced in comparison with laminar boundary layers. Effects of rotation make flow structures significantly different from two-dimensional flows. In the range of Reynolds number of model scale propellers, large portion of the blade are still in the transition region from laminar to turbulent flows. Therefore viscous flow pattern might be quite different on the blade of model propeller. The present method of calculation is to be useful for the research of scale effects, cavitation, and roughness effects of propeller blades.

• Journal of Agricultural Extension & Community Development
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• v.27 no.4
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• pp.159-171
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• 2020

This study aims to examine the needs analysis for agricultural management capabilities and farming practices that were emphasized by focusing to the inflow of farmers and the importance of the smooth succession. Data were collected from 134 farm successors. The Borich demand and the Locus for Focus model were hired for the study. Result were as follows. The competency group that the farm successors showed a high educational needs for was financial management. As for the detailed competencies that farm successors showed high educational needs for, based on Borich demand and the Locus for Focus model, the six detailed competencies of financial measures, financial analysis, financial management, sales planning, machine operation, and pest management were common and were derived as priorities. As for the direction of farming practice education for farm successors, based on these analysis results, education on machinery operation in the production sector should be expanded, and the management sector, more systematic and diverse education should be prepared to strengthen financial management capabilities.