• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.139.2-139.2
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• 2014

방사광 가속기의 저장링 진공용기처럼 콘덕턴스가 배기성능을 좌우하는 진공용기에서는 Strip NEG를 사용하여 분산 배기를 함으로서 원하는 평균진공도를 확보할 수가 있다. 일부 연구소에서는 진공용기 자체를 게터로 코팅하여 사용하고 있으나 그 제작비용이 만만치가 않다. 이 연구에서는 쉽게 구할 수 있는 동전모양의 작은 게터를 진공용기 내부에 길이 방향으로 일렬로 배치하여 분산배기가 실제 가능한 지 평가하였다. 게터는 진공용기 자체를 $180^{\circ}C$ 이상 베이크아웃할 때 활성화되도록 하였다. 실험은 단면적 $13cm^2$, 3 m 길이의 압출형 알루미늄 진공용기로 베이크아웃 온도에 따른 진공도 변화를 측정하여 그 성능을 평가하여 보고하고자 한다.

• Fire Science and Engineering
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• v.19 no.3 s.59
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• pp.44-51
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• 2005

The flame propagation velocity and the flame arrival time of methyl alcohol, which is widely used as a material of paint industry and organic synthesis, d mixing solvent, and an analytical reagent, were examined at different temperatures and concentrations. It was found that the smaller the vessel size, the easier and faster the combustion. The maximum combustion velocity was 200 cm/sec in the small vessel at $30^{\circ}C$. The flame arrival time was determined to be longer with larger vessels. and shorter with higher concentrations.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.1
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• pp.51-59
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• 1990

In this paper, a new variable structure control algorithm is proposed to reduce the reaching time on a phase plane. In the new method, a term proportional to the magnitude of the switching variables is added to the Morgan and Ozguners algorithm. When this algorithm is applied to second order systems the simulation results show that the new approach of the control algorithm is more effective than morgan's algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.2-5
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• 2015

본 연구에서는 프로그램을 전혀 해보지 않았고, 게임에는 관심 있는 초등학교 저학년을 대상으로 EPL 도구로서 스크래치를 이용한 SW교육의 교수 학습 모형을 개발하였다. 5단계 10차시로 분류하여 각 단계별 학습목표를 설정하고 교수 학습 목표를 결정하였다. 학습목표에 맞게 각 단계별 수업이 이루어지면 목표에 도달할 수 있도록 반복수업, 흥미 있는 수업, 이해도가 증가할 수 있도록 단계별 수업으로 구성하였다. 또한 SW교육 교수 학습 모형에서 각 차시별 목표를 설정하고 단계별 교수 학습 전략을 제공하여 목표에 도달할 수 있도록 유도하였다. 본 연구를 통해 초등학교 저학년에게 SW교육이 가능한지, 어느 정도 수준의 교육으로 이루어져야 하는 지, EPL 도구로서의 스크래치의 활용성은 어느 정도인지 등을 알아보고 SW교육에 수업자료로 활용하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.226-231
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• 2016

Binomial trees are used to price barrier options. Since barrier options are path dependent, option values of each node are calculated from binomial trees using backward induction. We use generalized Catalan numbers to determine the number of cases not reaching a barrier. We will generalize Catalan numbers by imposing upper and lower bounds. Reaching a barrier in binomial trees is determined by the difference between the number of up states and down states. If we count the cases that the differences between the up states and down states remain in a specific range, the probability of not reaching a barrier is obtained at a final node of the tree. With probabilities and option values at the final nodes of the tree, option prices are computable by discounting the expected option value at expiry. Without calculating option values in the middle nodes of binomial trees, option prices are computable only with final option values. We can obtain a probability distribution of exercising an option at expiry. Generalized Catalan numbers are expected to be applicable in many other areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.697-708
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• 2016

As the needs for fast wireless communication technology in various fields, including companies, individuals, etc., grows, many research projects related to the coverage of propagation are being carried out for plaining optimized communication services. On the other hand, there are some limitations in surveying and analyzing propagation in highland areas. To provide a better communication service of a new service, a range of radio environment conditions based on a wide radio bandwidth (selection of propagation model, correction of value in accordance with radio bandwidth, etc.) should be considered. In particular, radio environment conditions are becoming increasingly sophisticated. By the early detection of real-time changes in the radio spectrum, which is based on an examination and research of regional occupied band width condition, proper measures should be established. To make a proper solution of above, the basic real-time analysis of spectrum distribution status by regional groups is necessary. In addition, the establishment of prompt measures should be enable by stored or analyzed radio data. In an attempt to predict reliable propagation coverage, this thesis examines the limited propagation data with HTZ Warfare, which were collected from domestic high land sites faced with limited access. Furthermore, a comparative result value evaluation for an optimized propagation model was performed through testing simulations, and frequency-dependent and propagation model-dependent analysis.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.93-100
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• 2021

The purpose of this study is to find out the factors that affect the patient's exposure dose during the abdominal CT scan using the bolus tracking technique, and reducing the radiation exposure to the patient during the abdominal CT scan using the bolus tracking technique by adjusting the delay time according to the corresponding factor. The experiment was divided into two parts, and the first experiment was conducted with 300 patients There were 188 males and 112 females, and their average age was 58±12.18(19~85). In the second experiment, 150 subjects (100 males and 50 females) who were undergoing their follow-up examination among the first experiment subjects, and the difference in dose before and after was compared by applying the delay time according to the influencing factor. As a result of the first experiment, there was a relationship between the arrival time of the contrast media and the heart rate, and it was found that the arrival time decreased as the heart rate increased for both men and women. As a result of the second experiment, the average dose of CTDIvol and DLP before/after applying the delay time according to the heart rate decreased 4.98 mGy and 5.33 mGy·cm in the male group, and 3.54 mGy and 3.88 mGy·cm in the female group. By applying proper delay time according to the patient's heart rate during abdominal CT scan with the bolus tracking technique, the radiation exposure dose of the patient can be reduced.

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.2
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• pp.3-42
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• 2010

This study shows that the Warsaw Convention in Article 1 is not an international transport, origin, destination and all the Contracting Parties is not a purely domestic shipping does not apply to this Treaty. Therefore, in this case, liability and damages for the governing law is selected according to international law should be. In addition, in the case of international shipping and passenger air carrier of this treaty to govern the relationship, not all of which aim is the unification of certain rules. Product liability is the most important thing of all. As for the aircraft manufacturer's responsibility according to international law also does not select the applicable law is not. The Warsaw Convention Article 17 apply for the passenger's personal damages Article 2 Section 2 leads to the most prestigious type of damages, and subjective and objective with regard to the scope of international law are being committed. In this regard, Governing Law-related aircraft accidents leading to serious accidents in China of an aircraft crash in Nagoya, Japan, the airport can be. China Airlines accident of the aircraft are operated for the unification of the rules for international air transport on the Warsaw Convention as amended by Article 17, Article 18 of damages by the tort claims and claims based on damages caused by, or this cause of aircraft accidents air bus maker by the Corporation for damages in tort claims for damages claimed on the basis of solidarity is the case. In the case of these grand scale claim responsibility for the airline, air transport agreements to determine the applicable law of the contract is very complex. There for the contracts based on individual circumstances or origin, and by considering because each must be determined.

• 한국정보교육학회:학술대회논문집
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• 2007.08a
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• pp.267-272
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• 2007

학교 교육에서 문해력과 수리력에 비해 그 중요성이 간과되고 있는 공간 지각 능력과 도해력을 학습하기 위해서 학습자 중심의 지도 그리기 교육이 실제화 되어야 한다. 따라서 이 글에서는 보다 더 실제적 이고 효과적인 지도교육을 위한 지도그리기모듈을 구현하고자 한다. 특히 사회과의 경우 사고의 방법과 과정을 중요시 하는 교육목표를 가지고 있기 때문에, 현재의 저학년 초등교과교육 중 지도 그리기 학습의 문제점을 살펴보고 구체적 조작기의 아동을 위한 공간 능력의 향상과 구체물의 평면화 등 지도 그리기 교육의 목표를 수월하게 도달하기 위한 모듈을 구현하여 초등 지리 교육의 수월성과 함께 학습자의 수준에 맞는 흥미로운 학습을 도모하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.634-641
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• 2009

The goal of OSIC-series detection methods is to approach the ML performance with feasible complexity. However, since they sometimes suffer from the empty vector problem, they can not achieve the soft-output ML performance or many candidate vectors are required to achieve the soft-output ML performance. In this paper, we propose the novel detection method, which can generate the reliable soft-outputs without suffering from empty vector problem. The proposed detector can approach the near soft-output ML performance as well as hard-output. Further, the complexity study shows that the proposed detection method has the lowest complexity compared to the other detectors having the near ML performance.