• Membrane Journal
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• v.24 no.2
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• pp.136-141
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• 2014

In this study, cellulose acetate (CA) membrane was prepared by phase inversion precipitation and then evaluated the forward osmosis (FO) membrane performance. Differences in water flux and salt rejection between RO and FO with prepared membranes were observed. The different structure membranes were prepared with various solvent which evaluate the influence of membrane structure on permeability. The structure of the prepared membrane was confirmed through scanning electron microscopy (SEM) and the permeability changes were estimated using the bench-scale FO test equipment.

• Journal of the Korean Dietetic Association
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• v.16 no.4
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• pp.318-331
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• 2010

The objectives of this study were to investigate the status of accidents and to assess hazards in institutional foodservices in the Changwon and Masan areas. A survey was conducted from February 1 to March 31, 2009 using questionnaires, and 142 dietitians participated. The dietitians' perception of accident risks in workplace averaged 3.11 points. Forty-five percent of the respondents responded that accidents had occurred more than once between 2006 and 2008. In addition, 28.2% of the respondents experienced employee absences or turnover due to accidents during Year 2008. 'Musculoskelectal injuries or disorders (65.5%)', 'slips or falls (64.8%)', 'burns (57.7%)', and 'cuts and punctures (48.6%)' were the predominant accidents in foodservice. 'Knives (76 points)', 'steam kettles (41 points)', 'vegetable cutters (34 points)' and 'turn kettles (26 points)' were the equipment with severe accidents, such as burns or cut injuries. Among foodservice processes, 'carpal tunnel syndrome while washing (2.83 points)', 'burned by frying oil (2.64 points)', 'cut by sharp tools (2.55 points)', 'musculoskelectal injury by moving heavy weight food materials (2.41 points)', and 'injury by slipping on wet workplace floors and trenches (2.19 points)' were the most frequently occurring accidents at foodservice sites. To prevent safety accidents, dietitians' perceptions of safety supervision should be improved, and therefore, it is necessary they receive safety education.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.110-112
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• 2012

Education and training of technical staff for the new generation technological equipment has a vital importance for developing countries in order to maintain sustainable development and keep up with new generation technologies. Mechatronics the synergistic combination of mechanical, electronic and software engineering from an engineering perspective to serve the purposes of controlling advanced hybrid systems is a product of new generation technology which can be given as a sample to this phenomenon. Recent marine engines are combination of heavy industry with high technology. Nowadays, ships are built in full automation and equipped with computer controlled mechatronics systems. However, finding qualified officer and engineers who can operate, maintain, control and repair when it is required such full automatic systems with knowledge of a new generation system became a serious issue. Due to importance of this fact STCW Manila amendment has new training and certification requirements for electro-technical officers. In this paper, Mechatronics applications on ship are introduced, importance of it highlighted and a new syllabus is proposed for the training of marine engineers to be nurtured with mechatronics knowledge as it is required.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.88-94
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• 2013

As the results of analysis that are applying a heat pump using underground water as heat source of facility horticulture house, temperature change in house, growth of cultivated plants and the crop characteristic, the conclusion can be acquired as follows. It was possible to maintain the chamber temperature through operating heat pump with setting goal temperature at $16^{\circ}C$ and temperature variation at ${\pm}3^{\circ}C$. And cooling and heating coefficient of performance in heat pump system are different from setting room temperature and operation condition of equipment, totally in case that the setting temperature in house is low, the coefficient of performance and the in case that temperature departure is low. In case that the house does not heated, the result of the growth characteristic of cucumber planted last 50days is that cucumber grown in house equipped with heat pump is the most favorable growth characteristic due to maintaining a constant room temperature. After 90 days, the quantity and weight cucumber harvested in each house are averagely 9.8%, 13.1% increase and more heavy weight respectively. So it is researched that crop characteristic is superior.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.67-73
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• 2014

Construction equipment such as tower crane should be installed in a field without appropriate anchorage to cause a collapse of crane. The anchorage capacity can be varied with Anchor length, concrete strength, anchor diameter, hooked or non hooked these variables will be made and tested in the study. It is shown what anchorage capacity will be more effective case by case. Hooked and non-hooked rebar anchor concrete weight with dia 22mm rebar are shown with initial displacement at 170~220KN of hooked case and 200~210KN of non-hooked one which are linearly increased, without any ductility behavior with almost brittleness. Three(3) same test pieces are almost similarly behaviored without relation to hooked or non-hooked cases. It is found out that the bigger diameter of rebar becomes, the more resistant capacity could be made, but conversely ductility against sudden collapse similar to brittleness becomes the more insufficient. It is also found out that dia 16mm rebar could be more effectively applied to heavy support weight at construction sites.

• Journal of Construction Engineering and Project Management
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• v.7 no.2
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• pp.11-18
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• 2017

The cycle time of construction equipment for earthwork operations has a significant impact on project productivity. Elements that directly impact a haul vehicle's cycle time must be identified in order to accurately quantify the haul cycle time and implement strategies to decrease it. The objective of this research is to scientifically identify and quantify variables that have a significant impact on the cycle time of a dump truck used for earthwork. Real-time location data collected by GPS devices deployed in an active earthwork moving construction site was analyzed using statistical regression. External data including environmental components and haul road conditions were also collected periodically throughout the study duration. Several statistical analyses including a variance analysis and regression analysis were completed on the dump truck location data. Collected data was categorized by stage of the dump truck cycle. Results indicate that a dump truck's enter idle time, exit idle time, moving speed and driver visibility can significantly impact the dump truck cycle time. The contribution of this research is the identification and analysis of statistically significant correlations of variables within the cycle time.

• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.10-16
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.2
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• pp.13-18
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• 2010

To improve the performance of the bent-axis type axial piston pump driven by the tapered piston, it is necessary to know the driving characteristics and mechanism of the tapered piston and the cylinder block. Since each piston not only rotates on its axis and reciprocates in the cylinder bore, but also revolves around the axis of the driving shaft, it is difficult to analyze the driving mechanism theoretically. The theoretical mechanism for the bent-axis type axial piston pump is studied by using the geometrical method. The driving range of the tapered piston is determined by theoretical equations. The experimental results show that the cylinder block is driven by one tapered piston in a limited range and the core parameters such as driving factor of the piston and the ahead delay angle influenced performance of the bent-axis type axial piston pump.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1406-1410
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• 2015

The railway catenary systems consist of a complex structure, electrical and mechanical conditions are exposed to dangerous environment due to current collection between pantograph and catenary systems. These two types of conditions for the catenary systems are critically assessed for management and are becoming increasingly more dependent on reliable inspection system. In this paper, a new measurement system which enables inspection of catenary faults was studied and implemented. The system uses wavelength band of ultraviolet (UV) and IR (Infrared) to measure the insulation of corona and temperature of catenary wire. In order to determine the sensitivity of implemented system, the performance test such as distance detection range of UV camera and temperature resolution of IR camera were conducted, respectively. The field test of development system was also conducted in metro and high-speed line using mobile type UV and IR multi-composited measurement systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1912-1921
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• 1999

The equipments mounted on guided-missile undertake heavy vibrational disturbance. Sometimes the equipments mounted on guided-missile go wrong so that the guided-missile flies over unintended place. For the vibration isolation of the equipments mounted on guided-missile, active vibration control was performed. In the case of active vibration technique, the stiffness matrix and the mass matrix are derived based on FEM (ANSYS5.0). Model reduction was carried out and, as a result, we got 7 DOF mass and stiffness matrix. For the sake of FEM model identification, modal experiment was carried out. With the help of Sensitivity Analysis, the natural frequencies of FEM were tuned to those of Experiment. In this work, the Sky Hook and the LQG control theory were adopted for v iteration control using stacked piezoactuator. Experiments were performed with changing excitation frequency from 10 Hz upto 200 Hz and we got frequency response function of guided-missile equipments. The magnitude of 3rd mode of guided-missile equipments is 8.6 % that of Uncontrolled in Skyhook controller and is 3.4 % that of uncontrolled in LQG controller.