• 전자공학회논문지
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• 제50권10호
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• pp.239-244
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• 2013

본 논문에서는 고속 PMIC(Power Management Integrated Circuit) 회로를 위한 저전압 입력 보호기능을 가지는 UVLO(Under Voltage Lock Out) 기능이 탑재된 LDO(Low Drop-Out) 레귤레이터를 설계하였다. 설계된 LDO 레귤레이터는 밴드갭 기준전압 회로, 오차 증폭회로, 파워 트랜지스터 등으로 이루어지진다. LDO 레귤레이터는 5 V 전원전압으로부터 3.3 V 출력을 갖도록 설계되었으며, 저전압 입력보호 기능을 하는 UVLO 회로는 전원부와 파워 트랜지스터 사이에 삽입된다. 또한 UVLO는 5 V 구동전압에서, 하강 시 2.7 V 에서 LDO 레귤레이터 동작을 멈추게 하고, 구동전압 상승 시 4.0 V 에서 LDO 레귤레이터가 정상 동작한다. $1{\mu}m$ 20 V 고전압 CMOS 공정을 사용하여 모의실험 한 결과, 설계한 LDO 레귤레이터는 5.88 mV/V의 라인레귤레이션을 가지고, 부하전류가 0 mA에서 200 mA로 변할 때 27.5 uV/mA의 로드레귤레이션을 보였다.

• 한국환경복원기술학회지
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• 제9권4호
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• pp.67-75
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• 2006

This study compared with the object of designation and the management practices for Protection Forests between Korea and Japan to establish the management and development directions of Korea's Protection Forest. 1. Water conservation forest from total areas of Protection Forests occupied 90.6 % in Korea and 68.4 % in Japan, respectively. The water conservation forest was the most important function among the Protection Forest's functions in both countries. 2. The 10 million ha of Protection Forest in Japan increased for last 100 years. The 100 thousand ha per year was designated as Protection Forest. In contrast, The 655,535 ha of Protection Forest in Korea decreased for last 42 years with decreasing of 15,000 ha per year. 3. In Japan, Protection Forest can be managed by forest silvicultural practices such as forest harvest, thinning, and pruning to recover and improve the Protection Forest's functions. 4. In case of Korea, it is necessary to a mid- or long-term counter plan to increase the area of Protection Forest by the government, and needs to the recovery and improvement of Protection Forest's functions.

• Annals of Occupational and Environmental Medicine
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• 제34권
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• pp.42.1-42.11
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• 2022

Background: Occupational pesticide exposure is a potential risk for respiratory health effects. Most clinical studies on pesticide exposure were related to acute exposure, and only a few studies on chronic exposure have been conducted. This study investigated the chronic respiratory health status and the chronic effects of occupational pesticide exposures of farmers in Gyeonggi-do. Methods: Surveys and pulmonary function tests were conducted on 1,697 farmers in 16 regions of Gyeonggi-do. The structured questionnaire included demographic characteristics, medical history, recent respiratory symptoms and diseases, and work-related conditions, and was conducted through one-on-one interviews. The prevalence of respiratory diseases was compared by the odds ratios (ORs) at 95% confidence intervals (CIs) estimated by logistic regression analysis. Additional multivariate logistic regression analysis was also conducted. Results: Pesticide work groups showed significant association with an obstructive pattern in the lung function test (unadjusted OR, 2.38; 95% CI, 1.17-5.52). Selected work-related variables of pesticide exposure were 'start age,' 'cumulative duration,' 'mixing pesticides,' and 'protection(goggle).' The obstructive pattern of lung function test showed significant associations with mixing pesticides (OR, 2.30; 95% CI,1.07-5.46), and protection (goggle) use (OR, 0.34; 95% CI, 0.12-0.79). Conclusions: Mixing two or more pesticides showed a significant association. Wearing goggles can be seen as an indicator of awareness of the protective equipment and proper wearing of protective equipment, and loss of pulmonary function can be prevented when appropriate protection is worn.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.592-596
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• 2004

Corrosion is never avoided in the use of materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The proposed algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. This paper was studied the variation of potential and current density with environment factors, time and velocity, and the experimental results will be explained.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.105-112
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• 2006

The main function of a reactor protection system is to maintain the reactor core integrity and the reactor coolant system pressure boundary. Generally, the reactor protection system adopts the 2-out-of-m redundant architecture to assure a reliable operation. This paper describes the safety assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures such as the random hardware failures, common cause failures, operator errors, and the fault tolerance mechanisms implemented in the reactor protection system. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system, and applied to the reactor protection system being developed in Korea to identify design weak points from a safety point of view.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.896-898
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• 1998

Recent development of the digital computer and communication technology has made the concept of the adaptive protection possible, which is to adapt the operating parameters of the protective devices to the system changes, so that the best protection function can be maintained all the time. In order to achieve the adaptive protection, it is necessary to have the way to determine whether the change of the settings is needed under the certain system change or how good the current protection level is. This paper proposed the protectability index, which is a way to evaluate the protection level of the system under arbitary conditions and the operating strategy of the adaptive protection utilizing this index. It is based on an hierachical evaluation model and the evidence combination rule of the Dempster-Shafer theory.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.293-298
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ, But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations. In the result it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.461-466
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ. But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations In the result, it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• 대한임베디드공학회논문지
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• 제11권6호
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• pp.335-341
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• 2016

As information technology advances rapidly, various smart devices are becoming an essential element in our lives. Smart devices are providing services to users through applications up on the operating system. Operating systems have a variety of rules, such as scheduling applications and controlling hardwares. Among those rules, it is significant to protect private information in the information-oriented society. Therefore, isolation task, that makes certain memory space separated for each application, should highly be guaranteed. However, modern operating system offers the function to access the memory space from other applications for the sake of debugging. If this ability is misused, private information can be leaked or modified. Even though the access authority to memory is strictly managed, there exist cases found exploited. In this paper, we analyze the problems of the function provided in the Android environment that is the most popular and opened operating system. Also, we discuss how to avoid such kind of problems and verify with experiments.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.315-320
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• 1998

In this work, an automatic software verification method for Nuclear Power Plant (NPP) protection system is developed. This method utilizes Colored Petri net (CPN) for modeling and Prototype Verification system (PVS) for mathematical verification. In order to help flow-through from modeling by CPN to mathematical proof by PVS, a translator has been developed in this work. The combined method has been applied to a protection system function of Wolsong NPP SDS2(Steam Generator Low Level Trip)and found to be promising for further research and applications.