• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.08a
• /
• pp.3-13
• /
• 2004

The total tug capacity needed for berthing/de-berthing operations of a ship may vary depending on the ship type, size, loading conditions, and environmental circumstances. Traditionally, total tug capacity is determined based on the local guidelines of port authorities or on the rule of thumb. However, the social demands for the enhancement of ship safety at harbor and the economical demands for the cost-effectiveness of tug usage makes it necessary for port authorities to develop more reasonable and detailed guidelines on tug usage which takes various conditions into account. In this paper, the method to estimate the optimum tug capacity of VLCC is suggested by considering various ship conditions such as its size, loading conditions, and environmental circumstances such as wind, wave, tidal currents, and geographical characteristics of a terminal. This method is applied to a VLCC terminal located in Gwang-Yang Harbor of Korea and the results are compared with the local guidelines of the harbor, which shows that there may be a room for the amendment of local guidelines on tug usage.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.4
• /
• pp.83-91
• /
• 2006

At present, industry and researchers are looking for ways to reduce the use of lubricants because of ecological and economical reasons. Therefore, metal cutting is to move toward dry cutting or semi-dry cutting. One of the technologies is known as MQL(Minimum Quantity Lubrication) machining. This research presents an investigation into MQL machining with the objective of deriving the optimum cutting conditions for the turning process of SM4SC. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed rate, oil quantity and so on, with MQL and flood coolant. The surface roughness and cutting force results of tests were measured and the effects of cutting conditions were analyzed by the method of Analysis of Variance(ANOVA). From the experimental results and ANOVA, this research proposed optimal cutting conditions to improve the machinability in MQL turning process.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.4
• /
• pp.97-103
• /
• 2019

If the new town development project begins with inappropriate location then it will be difficult to recruit tenants and the proportion of the infrastructure cost could increase. It is necessary to evaluate the feasibility of the new town development projects to solve this problem. This study aims to identify the current status of the new town development projects and draw up evaluation criteria by examining advanced researches. To identify the importance of each village, we set up the weights through analytic hierarchy process. The evaluation criteria were classified into location conditions and economical efficiency. In the case of location conditions, it was classified into available size, geographical conditions, and accessibility. As a result of analyzing the questionnaire, it was subdivided into officially assessed land prices in case of economic efficiency. This study had some limitations, that is we focused on the location conditions and economic feasibility among other factors. Therefore further study should contain analysis more on socio-cultural aspects such as residents' cooperation or will for this project. By adding results later, we can make more reasonable decisions when we choose appropriate area.

• Journal of Ocean Engineering and Technology
• /
• v.37 no.5
• /
• pp.215-224
• /
• 2023

While melting glaciers due to global warming have facilitated the development of polar routes, Arctic vessels require reliable anti-icing methods to prevent hull icing. Currently, the existing anti-icing method, i.e., the heating coil method, has disadvantages, such as disconnection and power inefficiency. Therefore, a carbon nanotube-based surface heating element method was developed to address these limitations. In this study, the numerical analysis of the surface heating element method was performed using ANSYS. The numerical analysis included conjugate heat transfer and computational fluid dynamics to consider the conduction solids and the effects of wind speed and temperature in cold environments. The numerical analysis method of the surface heating element method was validated by comparing the experimental results of the heating coil method with the numerical analysis results (under the -30 ℃ conditions). The surface heating element method demonstrated significantly higher efficiency, ranging from 56.65-80.17%, depending on the conditions compared to the heating coil method. Moreover, even under extreme environmental conditions (-45 ℃), the surface heating element method satisfied anti-icing requirements. The surface heating element method is more efficient and economical than the heating coil method. However, proper heat flux calculation for environmental conditions is required to prevent excessive design.

• Journal of Satellite, Information and Communications
• /
• v.7 no.2
• /
• pp.42-46
• /
• 2012

This paper analyses technical and economical conditions which activate the use of mobile communication spectrum not to limit the growth of mobile broadband service because of mobile big data traffic and proposes the method which activate the use of mobile communication spectrum. To activate new mobile communication spectrum the expenditure and income of investment should be balanced. The activation of new mobile communication spectrum to process mobile big data traffic depends on technical and economical conditions, internal and external factors of service provider. The investment expenditure is relate to CAPEX, OPEX which is internal factors of service provider and to spectrum price which is external factor of service. The investment income is relate to tariff system which is internal factors of service provider and to spectrum neutrality which is external factor of service provider. The activation of new mobile communication spectrum can be implemented when the investment expenditure and investment income meet the balance including the spectrum price in the investment expenditure and the tariff system which is able to extend network and the income based on traffic increase by external contents in the investment income.

• Journal of Biosystems Engineering
• /
• v.13 no.4
• /
• pp.46-55
• /
• 1988

The objective of this study was to develop a computer measurement and control system which enable it possible to manage the natural air rough rice drying and storage properly and safely. The following contents of work were taken in this study in order to fulfill the above goal: 1) Design and construction of measurement system which can measure the rough rice drying conditions automatically and transfer them to computer system for data processing. 2) Development of a management software which can determine the need of fan operation by the analysis of drying and/or storage conditions. 3) Design and construction of a control system which deliver the computer decision of fan operation and make it on and off. 4) Technical and economical analysis of the computer measurement and control system development by the comparison experiments of the computer management and of the manual.

• Korean Journal of Health Education and Promotion
• /
• v.10 no.2
• /
• pp.22-31
• /
• 1993

Presently, in the countries, such as America and Japan which are better in socio-economical conditions than Korea, in Taiwan which is similar in them to us, and even in Thailand and Philippine which are thought lower in them, health education is taught as one of curricular subjects in elementary and secondary school levels. In Korea, however, the importance of teaching health education as a curricular subject has been recognized among many professionals of health since a long time ago. Along with current rapid development of polytechnique and industry, various kinds of serious health hazard have appeared even in our daily life, so it has been urgently needed that people have comprehensive knowledge and skills to resolve one's own health problems. Among various conditions needed to resolve the health problems in our society, it is one of the most effective precedures that health education is taught as a curricular subject at least in elementary and secondary school levels. For this, the followings are inevitable ; reformation of school health organization and laws involving health, development of teaching materials in health and training of health educators.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.11a
• /
• pp.39-42
• /
• 2012

Pusher-Loaded Scrapers are important construction equipment for large earthmoving operations. Production rates of a Pusher-Loaded Scraper vary greatly in accordance with the temperature or elevation, the equipment performance, haul speed, haul-road conditions, the method of loading, and Number of scrapers per one pusher. Determining of most economical scrapers fleet regarding the size of equipment, model name, and number of scrapers demands time-consuming calculation because it needs to reference of varied performance charts or tables and repeat complicated calculation. In this study, decision-making support system for the Optimal Pusher-loaded Scrapers Fleet is suggested for the purpose of calculating easily and handling effectively variables which are changed depend of the work conditions. The prototype of this program is developed using MATLAB. And the Database of Pusher-loaded Scraper embodies Performance chart & Retarder chart, soil properties, and calculation-support table.

• Journal of Korean Society of Rural Planning
• /
• v.8 no.3 s.17
• /
• pp.41-48
• /
• 2002

Spatially distributed characteristic of longevity regions analysed using GIS tools. Fundamental factors for long life are categorized into natural conditions and artificial conditions. Degree of longevity is defined and used as a key parameter in analyzing longevity region. It is visually shown that aging areas are moving with time and variances of social and economic status. It is concluded that the degree of longevity is increased with improving living quality because of improvement of economic activities and living environment. However, longevity regions of recent times have slightly reversed tendency against urban areas in the manner of moving toward areas where social and economical activities are relatively weaker.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.195-200
• /
• 2009

The objectives of this study are to analyze of energy consumption and operation conditions of each cooling system for gas and electric driven systems, and to compare operating cost for five different cooling systems; ice storage system, system air-condition, turbo chiller as the electric driven cooling systems, and absorption chiller and Gas driven Heat Pump (GHP) as the gas driven cooling systems. The sample designs are carried out based on the types of business, capacity, installation region and year.