• 항공우주기술
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• 제12권1호
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• pp.54-63
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• 2013

항공기의 자세제어를 담당하는 각각의 비행 조종면에 중복안정성 등의 이유로 여러 개의 작동기를 연결하여 사용하고 있다. 다중 작동기들이 동시에 정확하게 같은 위치로 이동하지 않으면 비행조종면에 변형이 발생한다. 그 결과 변형된 조종면이 원래 상태로 복원하려는 힘에 의해 작동기들 간에 force fighting이 발생한다. 게다가 force fighting은 각 장치들의 초기 허용 오차 등에 의해서도 발생한다. 다중 작동기간의 force fighting 현상은 제어정밀도에 영향을 미치고 피로파괴의 원인이 되어 작동기와 비행조종면의 수명을 단축할 수도 있다. 본 논문에서는 두 개의 서보작동기를 사용하는 시스템의 force fighting을 감소하기 위하여 힘되먹임제어를 사용하는 제어기를 설계하였다.

• Journal of Animal Science and Technology
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• 제65권5호
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• pp.1053-1064
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• 2023

Melatonin, which is produced from tryptophan, exerts various biological functions, including the regulation of circadian rhythm, sedative agents, and antioxidant ability. Therefore, we conducted two experiments with early-weaned rats and pigs to investigate the antioxidant and sedative effects of melatonin. In the rat experiment, a total of 42 rats (21 days old) were used, and the antioxidant capacity was determined. Next, we used 120 early-weaned piglets (21 days old) to conduct a 5-week experiment to evaluate the reductive effect of melatonin on energy-wasting movement, including roaming and fight states. Dietary melatonin supplementation significantly improved growth in both rats and pigs compared to the control groups. Additionally, rats fed a melatonin-supplemented diet showed advanced antioxidant capacity with a decrease in hepatic malondialdehyde concentration compared to rats fed a basal diet. Moreover, dietary melatonin ingestion increased resting and feeding behaviors and reduced roaming and fight behaviors during Days 8-21 compared to the control diet group. Collectively, early weaned animals given dietary melatonin supplementation showed improved growth through upregulation of hepatic antioxidant capacity and minimization of energy-wasting behavior, including roaming and fight states, after pigs' social hierarchy establishment.

• Journal of Ecology and Environment
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• 제38권4호
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• pp.443-450
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• 2015

The east coast of the Korean Peninsula is susceptible to fires because of the low rainfall in winter and spring, and large forest fires have occurred in this area. Lack of fresh water to combat fires has hampered efforts to prevent widespread forest fires in this region. Seawater has not been used as a suppressant because of possible detrimental effects of salt. We investigated the mobility of saline water in the forest soil and their effect on the microbial activity. Using a fire-fighting helicopter, seawater was sprayed over three plots (50 × 100 m) located on the eastern slope of the Baekdu mountain range in South Korea in April, 2011. We sampled the soil in April 4, May 20, and August 5 to determine the amount of salt that remained in the soil. The electrical conductivity value of the soil decreased to <400 μS/cm over a 1-month period. Approximately, four months after the application of seawater, the electrical conductivity value and Na⁺ content in all treatment plots did not significantly differ to those of the control plot, and total microbial activity also recovered to that of the control. Our results indicate that the amount of rainfall, soil physical-chemical properties, and topological factors may be a critical factor determining the mobility of saline water in forest soil.

• Journal of applied mathematics & informatics
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• 제40권5_6호
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• pp.857-871
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• 2022

In this work, we formulated a mathematical model for divorce in marriage and extended in to an optimal control model. Firstly, we qualitatively established the model positivity and boundedness. Also we saw sensitivity analysis of the model and identified the positive and negative indices parameters. An optimal control model were developed by incorporating three time dependent control strategies (couple relationship education, reducing getting married too young & consulting separators to renew their marriage) on the deterministic model. The Pontryagin's maximum principle were used for the derivation of necessary conditions of the optimal control problem. Finally, with Newton's forward and backward sweep method numerical simulation were performed on optimality system by considering four integrated strategies. So that we reached to a result that using all three strategies simultaneously (the strategy D) is an optimal control in order to effectively control marriage divorce over a specified period of time. From this we conclude that, policymakers and stakeholders should use the indicated control strategy at a time in order to fight against Divorce in a population.

• 제어로봇시스템학회논문지
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• 제6권12호
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• pp.1070-1078
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• 2000

A nonlinear adaptive flight control system is proposed using a backstepping controller with neural network controller. The backstepping controller is used to stabilize all state variables simultaneously without the two-timescale assumption that separates the fast dynamics, involving the angular rates of the aircraft, from the slow dynamics which includes angle of attack, sideslip angle, and bank angle. It is assumed that the aerodynamic coefficients include uncertainty, and an adaptive controller based on neural networks is used to compensate for the effect of the aerodynamic modeling error. It is shown by the Lyapunov stability theorem that the tracking errors and the weights of neural networks exponentially converge to a compact set. Finally, nonlinear six-degree-of-freedom simulation results for an F-16 aircraft model are presented to demonstrate the effectiveness of the proposed control law.

• 한국IT서비스학회지
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• 제12권3호
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• pp.179-193
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• 2013

E-Government refers to government to use ICT (information and communications technology) to work more effectively, share information and deliver better services to the public. With ICT, e-Government has increased transparency of governments. However even there has been much trial for transparency, corruption has been growing with the form of e-corruption. While external threats such as hackers and viruses can have serious consequences, currently most crime involving emerging technology is carried out by insiders i.e. employees in the e-government. Among the many tools being developed to fight e-corruption, there has been much focus lately on internal control system. So, South Korea developed and test-operated "Barum e-system" for internal control last year. This research establishes legal basis, information system link and privacy policy for settlement of this information system through legal review.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.148-151
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• 2007

The CF(Counter-fire) is neutralizing enemy's all command control systems and fire support elements. It will weaken a battle continuous ability and an intension to fight. At the beginning of the CF is obtaining locations of targets using various detection assets. CF command center processes acquired target information and send it to attacking equipments. The targets are classified into two classes, preplanned target and target of opportunity The target of opportunity is potential threaten, so it needs to take a immediate and exact process for determining location of target of opportunity. This paper proposes the real-time processing algorithm for offensive weapons to strike target of opportunity, and presents the result of its performance.

• Journal of Platform Technology
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• 제9권1호
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• pp.3-14
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• 2021

Cognitive Radio network (CR) is a promising paradigm that helps the unlicensed user (Secondary User) to analyse the spectrum and coordinate the spectrum access to support the creation of common control channel (CCC). The cooperation of secondary users and broadcasting between them is done through transmitting messages in CCC. In case, if the control channels may get jammed and it may directly degrade the network's performance and under such scenario jammers will devastate the control channels. Hopping sequences may be one of the predominant approaches and it may be used to fight against this problem to confront jammer. The jamming attack can be alleviated using one of the game modelling approach and in this proposed scheme stochastic games has been analysed with more single users to provide the flexible control channels against intrusive attacks by mentioning the states of each player, strategies ,actions and players reward. The proposed work uses a modern player action and better strategic view on game theoretic modelling is stochastic game theory has been taken in to consideration and applied to prevent the jamming attack in CR network. The selection of decision is based on Q learning approach to mitigate the jamming nodes using the optimal MDP decision process

• 보건행정학회지
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• 제30권4호
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• pp.431-432
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• 2020

Coronavirus disease 2019 (COVID-19) has been going on for nearly a year. As of December 1, 2020, more than 60 million confirmed cases and 1.4 million deaths have occurred in 220 countries and territories. There is no effective treatment for COVID-19 so far, and vaccines are being developed. However, the vaccine of COVID-19 can be freed from COVID-19 only if there are positive answers to some questions: "Aren't there any major side effects from the vaccine?"; "Is the vaccine effective for enough time?"; "Does the vaccine sufficiently reduce the mortality rate?"; and "Does the vaccine sufficiently reduce the reproduction number?" The fight against COVID-19 will continue for a long time. Therefore, we need to respond by developing the evidence for control of COVID-19, the emerging infectious disease. Extensive quarantine measures in the early stages of COVID-19 need to be elaborated through developing the evidence. Korea Disease Control and Prevention Agency should establish a database for evidence developing COVID-19 control. In this database, based on more than 3 million tested individuals, epidemiological investigation results, health insurance claims data, and government data such as the Ministry of Public Administration and Security, etc. should be linked. It is necessary to disclose this database to academia, etc. to create the evidences of COVID-19 and manage COVID-19 through these. And through the developed evidences, guidelines for physical health and mental health in the era of Corona 19 should be developed.

• 한국컴퓨터정보학회논문지
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• 제23권8호
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• pp.143-149
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• 2018

Recently, President Donald Trump signed FOSTA (Fight Online Sex Trafficking Act) in April 11, 2018, which makes online service no more immune from civil liability for the action of third party facilitating sex trafficking content. Although it is also important to enhance security regulations and cognition on law, but it will be economically more effective to put more energy on preventing recidivism. For John School in Korea, it should increase implementation rate by putting core manpower and budget for preventing needs of sex purchase and then, check operation method and efficacy to improve the actual program. One way is first, empirical analysis and data is required on efficacy of John School program. Second, should have clear definition in Special Sex Trade Law. Third, more strick regulation for selecting participant is required. Fourth, more manpower and budget is required. Fifth, charging the participant for educational fee shall be reviewed. Sixth, educational program should be reviewed. The most important point of education is to make those criminals feel guilty about financially purchasing the sex, basically making them to recognize that it is ethically wrong. However, the current education system contains no clear explanation about the ethical issue of such problem but focusing more on other factors such as sexual disease and structural problem of sexual business. Therefore, this failed to deliver the right psychological training to those criminals without any ethical control. Knowing why women feel hurt when having unwanted sexual relationship by being paid is required part in terms of education for preventing sex trafficking.