• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.57-63
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• 1997

Uninterruptible power supply(UPS) system should provide a good quality and stable power supply no matter what the condition of the raw mains. And when the mains fails, it must provide uninterrupted power to the load for a specified time. In this paper. discrete control system is introduced to improve output waveforms of UPS. This technique can be obtained output voltage by discrete data of synchronous control and voltage control to various loac. And then, the compact and light UPS can be realized by remove of the analog circuit and simulation and ezperinentation were performed with this control algofihtm. The experiment result show the effectiveness of proposed UPS system uwing the discrete control techjique.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.127-152
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• 2020

Despite growing international cooperation for maintenance of international peace and security, wars continue to occur due to conflicted state interests. Continuing conflicts has advanced development of various weapon systems such as global integrated intelligence, surveillance and reconnaissance. However, with a big increase in the number of civilian casualties caused by the weapon systems development, the international community has also advanced diplomatic efforts to minimize deaths of civilian and military personnel. Therefore, it is essential to observe the principle of discrimination between combatants and non-combatants when operating unmanned aerial vehicles (UAVs), better known as drones. Drones have become more capable of distinguishing combatants from non-combatants due to its high-tech prowess. In the operation of drones, any parties involved in combat or the war are responsible for mounting civilian casualties. In addition, it should comply with the principle of proportionality that calls for a balance between results of such action and expected military advantage anticipated from the attack. The rule of proportionality prohibits use of military force which may be expected to cause excessive civilian harm. Drones have been able to track and monitor targets for hours and select the accurate locations of the targets. The aim is to reduce civilian losses and damage to a minimum. Drones meet the standards of Article 51.4 of the Additional Protocol.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.429-436
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• 2001

The present study was performed to investigate the effect of iohexol-ethanol mixture and barium-ethanol mixture on the induction of transcatheter renal artery embolization in healthy 18 dogs, which were divided into two groups of 9 dogs and the 9 dogs were divided into 3 subgroups of 3 dogs. The renal artery embolization was undertaken unilaterally with the dose of 1.5, 2.0, and 3.0 ml/kg iohexol-ehtanol mixture and with the dose of 0.2, 0.4, and 0.8 ml/kg barium-ethanol mixture. And serum chemistry on 0, 1,3, 7, and 14 days, intravenous pyelography on 7days, angiography on 14 days, and histopathology on 14 days were evaluated. Serum BUN and creatinine concentration of two groups with iohexol-ethanol mixture and barium-ethanol mixture administration were mildly increased a t 1 day after injection of embolic materials and then returned to baseline. No significant changes in BUN and creatinine levels occurred in any of dogs. In all dogs with the dose of 1.5 ml/kg iohexol-ethanol mixture, the renal arteries were not embolized. All dogs with the dose of 3.0 ml/kg died. In all dogs with the dose of 2.10 ml/kg, the treated arteries were completely occluded. In barium-ethanol mixture administered group, the renal artery in one dog with the dose of 0.2 ml/kg was not embolized. In all dogs with the dose of 0.8 ml/kg, the renal arteries were completely embolized, but loac overembolization occured in two dogs. All animals with the dose of 0.4 ml/kg had effective embolization and no evidence of radiopaque barium opacity in systemic arteries distal to the renal-artery was found. All embolized kidneys were shrunk and decreased in size in gross examination and were shown diffuse necrosis in histopathologic examination. In the present study, renal arteries were embolized with the dose of 2.0 ml/kg iohexol-ethanol mixture or 0.4 ml/kg barium-ethanol mixture. And it is considered that the dose had a satisfactory embolic effect.