• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.1
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• pp.10-19
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• 2022

Recently, the Defense Advanced Research Projects Agency(DARPA) in the United States is studying a new concept of war called Mosaic Warfare, and MUM-T(Manned-Unmanned Teaming) through the division of missions between expensive manned and inexpensive unmanned aircraft is at the center. This study began with the aim of deriving the priority of autonomous functions according to the role of unmanned aerial vehicles in the present and present collaboration that is emerging along with the concept of mosaic warfare. The autonomous function of unmanned aerial vehicles between the presence and absence collaboration may vary in priority depending on the tactical operation of unmanned aerial vehicles, such as air-to-air, air-to-ground, and surveillance and reconnaissance. In this paper, ACE (Air Combat Evaluation), Skyborg, and Longshot, which are recently studied by DARPA, derive the priority of autonomous functions according to air-to-air collaboration, and use AHP analysis. The results of this study are meaningful in that it is possible to recognize the priorities of autonomous functions necessary for unmanned aircraft in order to develop unmanned aerial vehicles according to the priority of autonomous functions and to construct a roadmap for technology implementation. Furthermore, it is believed that the mass production and utilization of unmanned air vehicles will increase if one unmanned air vehicle platform with only essential functions necessary for air-to-air, air-to-air, and surveillance is developed and autonomous functions are expanded in the form of modules according to the tactical operation concept.

• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.289-299
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• 2013

Objectives: For the field application of the dielectric barrier discharge plasma reactor, scale-up of the plasma reactor is needed. This study investigated the possibility of inactivation of microorganisms in sewage using pilot multi-plasma reactor. We also considered the possibility of degradation of total organic carbon (TOC) and nonbiodegradable matter ($UV_{254}$) in sewage. Methods: The pilot plasma reactor consists of plasma reactor with three plasma modules (discharge electrode and quartz dielectric tube), liquid-gas mixer, high voltage transformers, gas supply equipment and a liquid circulation system. In order to determine the operating conditions of the pilot plasma reactor, we performed experiments on the operation parameters such as gas and liquid flow rate and electric discharge voltage. Results: The experimental results showed that optimum operation conditions for the pilot plasma reactor in batch experiments were 1 L/min air flow rate), 4 L/min liquid circulation rate, and 13 kV electric discharge voltage, respectively. The main operation factor of the pilot plasma process was the high voltage. In continuous operation of the air plasma process, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal condition of 13 kV were $10^{2.24}$ CFU/mL, 56.5% and 8.6%, respectively, while in oxygen plasma process at 10 kV, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal conditions were $10^{1.0}$ CFU/mL, 73.3% and 24.4%, respectively. Electric power was increased exponentially with the increase in high voltage ($R^2$ = 0.9964). Electric power = $0.0492{\times}\exp^{(0.6027{\times}lectric\;discharge\;voltage)}$ Conclusions: Inactivation of microorganisms in sewage effluent using the pilot plasma process was done. The performance of oxygen plasma process was superior to air plasma process. The power consumption of oxygen plasma process was less than that of air plasma process. However, it was considered that the final evaluation of air and oxygen plasma must be evaluated by considering low power consumption, high process performance, operating costs and facility expenses of an oxygen generator.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2239-2244
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• 2014

Objective: To investigate the effects of secondary left-sided portal hypertension (LSPH) on the radical operation rate of patients with pancreatic cancer and systemically evaluate the prognosis of patients with LSPH secondary to pancreatic cancer after radical surgery. Materials and Methods: The data of patients with pancreatic cancer who underwent laparotomy over a 15-year period in Department of Hepatobiliary Surgery of Chinese PLA Air Force General Hospital from Jan. 1, 1997, to Jun. 30, 2012 was retrospectively reviewed. Results: A total of 362 patients with pancreatic cancer after laparotomy were selected, including 73 with LSPH and 289 without LSPH. Thirty-five patients with LSPH (47.9%) and 147 without non-LSPH (50.9%) respectively underwent radical operations. No significant difference was found between these two groups regarding the total resection rate and stratified radical resection rate according to different pathological types and cancer locations. The mean and median survival time of patients after radical operation in LSPH group were $13.9{\pm}1.3$ months and 14.8 months, respectively, while those in non-LSPH group were $22.6{\pm}1.4$ months and 18.4 months, respectively(P<0.05). Conclusions: Radical operations for pancreatic cancer and secondary LSPH are safe and effective. Because high-grade malignancy and poor prognosis are closely associated, the decision for radical surgery should be made more meticulously for the patients with pancreatic cancer.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.104-113
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• 2019

There are keen competitions among the air operators to recruit competent pilots, which could be adversely affect the safe operation of aircraft. This study is aimed to identify the correlation between the flight experience of the pilot of the air transport operator and competency on visual approach operation. About 2,400 sets of flight training data of several pilots of an air transport operator was analysed for this study. The analysis showed that most captains were able to make stabilized visual approach regardless of his/her flight experience of any type of aircraft, while the first officers were able to make a stabilized visual approach with more than 1,500 hours of flight experience for each rated type of aircraft. This should be considered during making policies for the supply and demand of pilots for the safe operation of air transport.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.788-797
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• 2011

This paper analyzes the accuracy on the approach and landing of aircraft to an airport through comparison with airbase Precision Approach Radar and aircraft track data of DGPS equipped in aircraft. The proposed analysis result could be a basis for verifying the possibility that DGPS can be utilized in Airbase precision approach and landing. Position identification capability of widely used commercial DGPS is fairly accurate on latitude and longitude, while there is a slight error for being used in an airbase accurate approach and landing of Category I precision when it comes to altitude. Thus, we tested accuracy by analyzing actual flight track data of high performance aircraft to verify the accuracy of the airbase approach and landing using DGPS. Through the research, we developed instrumentation to compare PAR track data with DGPS track data, which can be used in reducing the number of PAR verification Flight utilizing it as a system measuring PAR accuracy at PAR installation phase.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.74-83
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• 2011

In this paper, we propose an architecture design of military operation system utilizing cellular networks. The main contribution of this paper is to provide a cost-effective military operation solution for ground forces, which is based on IT(information technology). By employing the cellular phones of officers' and non-commissioned officers' as the tools of operational communication, the proposed system can be constructed in the minimum duration and be built on the four components: command and control system, gateway, security system, and terminal(cell phone). This system is most effective for the warfare of limited area, but the effectiveness does not decrease under the total war covering the whole land of Korea. For the environmental change of near future, expanded architecture is also provided to utilize the functionalities of smart phones.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.784-794
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• 1998

The present study has been directed at developing thermal models to investigate the dynamic behavior of a solar cooling system including an absorption chiller, solar collectors, a hot water storage tank, a fan coil unit, and the air-conditioned space. The operation of the system was simulated for 8 hours in two different operation modes. In the mode 1, the system operated without any capacity control.0 the mode 2, an auxiliary boiler supplied heat to the generator if hot water temperature became lower than a certain value. Moreover, the mass flow rate of hot water to the generator was controlled by comparing the instantaneous room air temperature with the design value. The variation of temperature and concentration in the system components and that of heat transfer rates in the system were obtained for both modes of operation. It was found that the room temperature was maintained near the desired value in the mode 2 by supplying auxiliary heat or controlling the mass flow rate of hot water, while the deviation of room temperature was quite great in the mode 2.

• Journal of Drive and Control
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• v.15 no.2
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• pp.32-37
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• 2018

The power plants use turbine output control devices to supply or shut off steam to high pressure and low-pressure steam turbines connected to generators. This turbine output control device is driven by a hydraulic servo actuator. The gas flows into the hydraulic servo actuator during periodic inspection or normal operation, and the resulting adiabatic compression of the gas raises the internal temperature of the actuator to $500^{\circ}C$. This temperature increase causes the seals to burn and show wear and tear, resulting in failure. In this study, an air vent valve was installed to allow gas inside the hydraulic servo actuator to flow large quantities of air at the beginning of the operation and after the periodic inspection. Gas was passed through for only minute flow during normal operation of the power plant. By applying the air vent valve, it improves the reliability of the hydraulic servo actuator by discharge the gas appropriately to improve the life of the seal.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.517-524
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• 2004

In this paper the novel operation method of concentration winding BLDC motor of air conditioner compressor to improve efficiency is proposed.. Because it demands generally the need of more confidential sensorless operation, it Is hard to apply to three phases - three excited operation by reason of intricate calculations. In order to improve the defects of 120 degrees electrical conduction method, a novel PW Pattern is proposed. Established three phases - two excited system on real load air conditioner is used in experiment.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.66-72
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• 2008

In this study, the ground source heat pump was installed at a research center in Jeju Island to verify the performance of the system and to give an information for a economic feasibility. The performance test was conducted until the heat storage tank temperature reached at $5^{\circ}C$ from $50^{\circ}C$ in the cooling operation, and until the storage temperature goes up to $50^{\circ}C$ from $10^{\circ}C$ in the heating mode. As results, the system performance shows that $2.2{\sim}3.5$ for the cooling operation and $2.5{\sim}3.5$ for heating operation. It is found that the underground is good heat source for the heat pump with $3{\sim}10^{\circ}C$ variation range. The ground source heat pump could be connected one of air conditioning system without any problem in system performance. Based on the economic analysis, the initial cost for the ground source heat pump will be compensated after 4 years operation. If the system runs 20 years, approximately 300 million Won will be saved when the air conditioning system adapt the ground source heat pump based on Life Cycle Cost analysis.