• 디지털산업정보학회논문지
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• 제13권1호
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• pp.59-67
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• 2017

In recent years, cyber terror that break into major institution's information system and destroy and paralyzed important information occurs frequently. Some countries do dangerous acts such as train hackers and order hackers to hack important industrial confidential documents which are core of national competitiveness to reduce the competitiveness of the country and cause social confusion. In this thesis, it will study problems of cyber terror to help people to use Internet in web environment that safe from cyber terror and to avoid the risk from cyber terror such as malware and DDos. This thesis is organized as following. In second chapter, it will look thorough the research that are related to cyber terror. In third chapter, it will study attack types of cyber terror. In fourth chapter, to defend from cyber violence, it will suggest safe solution. In fifth chapter, it will end with conclusion. Finally, to prevent urgent incidents like North Korean Cyber-attack, every Internet user must indicate their recognition on Internet security and it is significant to make a quick response treatment to create the safe online environment.

• 한국유기농업학회지
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• 제2권1호
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• pp.16-23
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• 1993

The traditional farming method has very long history in the process of agricultural development. The application of chemical fertilizers production became most popular to increase quantities of agricultural production. The United States of America is one of largest countries in the world. There are at present 50 States and farming conditions are very different from each individual States. There are increasing trend of agricultural production by applying chemical fertilizers as well as sprays during last 50 years(1940-90). The disadvantages of conventional farming method were to destroy nature and human life. There were some other kinds of disadvantages such as nitriated contamination in drinking water both for human being and animals. The alternative farming method is one of new farming method reducing and/of non-application of chemical fertilizers and sprays in agricultural production. There is less economic research on alternative farming system about $5.444 economic advatages in organic farms comparing commercial farms at the same area. There are advantage of higher unit price level in orgnic products, decreasing chemical costs as well as effect of crop combinations. It is certainly necessary to have more empirical research on economic and management of alternative farming method in the United States of America. However, if there is economic advantage in alternative farming methods, the future development possibility of alternative farming method can be very bright in vear future. There might be more advantages such as soil conservation, better quality of agricultural products, better health conditions of farmer's and consumer's as well as keeping healthy environment of rural and urban areas.

• 보존과학연구
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• 통권31호
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• pp.17-30
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• 2010

There were excavated many relics about 200 pieces including gilt-bronze cap, gilt-bronze shoes, bronze mirror and armor, etc. in Ahndong tumulus, Gildu-ri, Goheung. The National Research Institute of Cultural Heritage was undertaking excavation of major damaged relics that were corroded by several environment and were destroyed by a lump of earth. Shoes are consolidated with soils in order to stop destroy during excavation. And these are relocated in order to treat for conservation. Before treatment, X-ray radiography and CT(Computed Tomography) are used in order to examine the original surface and the shape of shoes. As a result, we confirm the condition of shoes. If soils are removed, gilt-bronze shoes are crumbling into little pieces because gilt-bronze shoes are damaged by corrosion and deformation. So, shoes are consolidating with inner soils and are removing outer soils. Throughout conservation treatment, shoes recovered original form and inner soils are consolidated in order to keep the shape of shoes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.792-796
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• 2006

In recent years, the semiconductor industry and the optical industry is developed rapidly. The recent demand has expanded for optical components such as a optical lens, a optical semiconductor and a measuring instrument. Object transport systems are driven typically by the magnetic field and the conveyer belt. Recent industry requires more faster and efficient transport system. However, conventional transport systems are not adequate for transportation of optical elements and semiconductors. Because conveyor belts can damage precision optical elements by the contact force and magnetic systems can destroy the inner structure of semiconductor by the magnetic field. In this paper, the levitation transport system using ultrasonic wave is developed for transporting precision elements without damages. This transport system is using 2-mode ultrasonic wave excitation and flexural beam modes shapes are evaluated. It compared simulation results with experimental results

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.670-677
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• 1991

All models of dynamical systems invariably have some measure of uncertainties associated with some of their dynamics. The recent approaches to establish robustness of stabilizing feedback control against the possible uncertainties have a serious limitation, that is, their applicability only to the systems that satisfy the matching conditions. Such conditions are rarely met in general applications. If a particular system satisfies the matching conditions, the addition of an actuator will destroy the satisfaction of such conditions. In this paper, we develop robust control algorithm for uncertain multivariable systems in which the matching conditions are not necessarily met. In order to eliminate an influence over partial state variables due to unknown constant disturbances we perform the appropriate block-decomposition for a given system. Functional observers are introduced to estimate the unknown constant disturbances. The sliding mode controller is designed in such a way that the partial state variables in the state-space are directed towards switching surfaces and regulated to the origin asymptotically. Numerical examples are discussed as illustrations.

• 대한한방내과학회지
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• 제31권4호
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• pp.837-845
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• 2010

It has been shown that bilateral decrease of point H4,5,6 in Ryodoraku test is related with gastric dysmotility. This suggested that the system of Kyung-Rak related with anatomical gastric disease may not be the Stomach Meridian, in the view that the system of Kyung-Rak is similar to that of Ryodoraku, and which was not consistent with classical contents of Kyung-Rak principle. Therefore, this paper was done to investigate whether bilateral decrease of point H4,5,6 is a general sign of common gastric disease in Ryodoraku test and to study its relation between Kyung-Rak principle and autonomic nervous system as a mediator explaining Ryodoraku response. As shown in the results of this study, different electrical response of Ryodoraku between patients with dyspepsia of gastric dysmotility and gastric ulcer revealed discrepancy of location indicating anatomical stomach between Kyung-Rak principle and Ryodoraku and instability of explanation of autonomic nerve theory to Ryodoraku. Thus, it presented the possibility that artificial application of Kyung-Rak principle against Ryodoraku may destroy its originality in the clinical field. To correctly use Ryodoraku in the diagnosis or evaluation of disease, Ryodoraku test should be used according to Nakatani's suggestion and clinical indication of which is limited to the diseases complicated with dysfunction of the autonomic nervous system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.93-94
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• 2011

This paper analyzes the shaft torsion of a doubly-fed induction generator (DFIG) for a wind farm collector system fault. When a fault occurs, the active power of the DFIG cannot be transmitted to the grid and thus accelerates the rotation of both the blade and the rotor. Due to the different inertia of these, the angle of deviation fluctuates and the shaft torsion is occurred. This becomes much severe when the rotational speed of the blade exceeds a threshold, which activating the pitch control to reduce the mechanical power. The torque, which can be sixty times larger than that in the steady state, may destroy the shaft. The shaft torsion phenomena are simulated using the EMTP-RV simulator. The results indicate that when a wind farm collector system fault occurs, a severe shaft torsion is occurred due to the activation of the pitch control.

• 한국비블리아학회지
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• 제11권2호
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• pp.83-112
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• 2000

지식경제가 기반이 되는 21세기에 인터넷의 개방성, 글로벌성, 접근용이성이 기술, 산업 그리고 문화의 새로운 융합과 발전을 구축하는 중심 축이 되고 있다. 그러나, 사이버공간에서 발생되고 있는 정보화의 역기능(인터넷을 이용한 각종범죄, 정보시스템 불법침입 및 파괴, 불건전정보의 유통, 개인의 프라이버시 침해, 개인정보의 오남용 등)들은 갈수록 빈번하고 지능화되고 있어 심각한 사회적 혼란과 국가의 전략적, 행정적, 경제적으로 막대한 손실은 물론 군사활동마저 마비시키고 있는 실정이다. 따라서 본 글에서는 사이버공간에서의 범죄행위를 예방하고 차단시킬 수 있는 정보보호와 기술 그리고 그 패러다임을 조사 분석하여 기술하고 정보보호기술과 산업현황을 국내외적으로 알아본 다음 정보보호기술의 측면에서 바람직한 활성화 방안을 제시한다.

• 한국세라믹학회지
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• 제38권3호
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• pp.212-217
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• 2001

The influence of granules characteristics and compaction pressure on the microstructure and mechanical properties of sintered as a function of slurry dispersion state. The characteristics and the compaction behavior of the spray dried alumina granules considerably affected the microstructure as well as the mechanical properties of the sintered body. In the green bodies formed with granules prepared with a dispersed slurry, the granules with dimple clearly existed and caused pore defects in sintered body. These dimples were clearly present even in the green body prepared at 180 MPa. The pores between the granules were not removed during pressing and sintering, and remained in the sintered body. In contrast, in the granules fabricated from a flocculated slurry, the destroy of granules at the contact points was observed with increasing pressure. Sintered bodies fabricated with fewer defects showed strength increase. For the sample fabricated with flocculated slurry, the pores at the boundaries of granules were small and more irregular shape compared with those of dispersed slurry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.170-172
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• 2003

Among low power servo applications, classical DC motors are very popular because they are reasonably cheap and easy to control. The main disadvantage is the mechanical collector which has only a limited life period. Also, brush sparking can destroy the rotor coil, generate EMC problems. So permanent magnet brushless do motors and drives are being used increasingly in a wide range of applications. This has been made possible with the advantages of high performance permanent magnets with high coercively and residual magnetic, which make it possible for the PM to have superior power density, torque to inertia ratio and efficiency, when compared to an induction or conventional dc machine. This paper presents the design of a PM brushless dc motor drive simplistically operates as a classical dc motor. The BLDC motor drive system for this paper composes to the power integrated circuits, the one chip device. And several simple semiconductors add to drive system for a motor drive system simplistically operates as a conventional dc motor. Test results confirmed the feasibility of the proposed motor drive system design.