• Journal of Applied Reliability
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• v.17 no.3
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• pp.213-223
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• 2017

Purpose: The purpose of this study is to arrange the life data analysis literatures based on the Bayesian method quantitatively and provide it as tables. Methods: The Bayesian method produces a more accurate estimates of other traditional methods in a small sample size, and it requires specific algorithm and prior information. Based on these three characteristics of the Bayesian method, the criteria for classifying the literature were taken into account. Results: In many studies, there are comparisons of estimation methods for the Bayesian method and maximum likelihood estimation (MLE), and sample size was greater than 10 and not more than 25. In probability distributions, a variety of distributions were found in addition to the distributions of Weibull commonly used in life data analysis, and MCMC and Lindley's Approximation were used evenly. Finally, Gamma, Uniform, Jeffrey and extension of Jeffrey distributions were evenly used as prior information. Conclusion: To verify the characteristics of the Bayesian method which are more superior to other methods in a smaller sample size, studies in less than 10 samples should be carried out. Also, comparative study is required by various distributions, thereby providing guidelines necessary.

• Asian Journal of Turfgrass Science
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• v.2 no.1
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• pp.41-48
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• 1988

Research was conducted to obtain easy and secure methods for promoting germination of Korean lawngrass (Zoysia japonic a Steud.) seed. The effect of sodium hypochiorite (NaOCl) treatment on germination of seeds was compared with that of potassium hydroxide (KOH) treatment under conditions of duration of seed storage after harvest and temperature of treatment. Emergence of seedlings from soil and micro-flora infection rate among seed treatments were investigated. 1. The promotion of germination was much more evident in seeds treated with 4% NaOCl for 8 and 10 hours than in seeds treated with 25% or 30% KOH for 30 and 40 minutes. Longer durations of storage before seed treatment in KOH than in NaOCl were required to initiate enough germination. 2. Differences in temperature of treatment with NaOCT did not have much influence on germination of seeds and treatment temperature of 15˚C was better than that of 200˚C and 300˚C for promoting germination. But seed treatment with KOH significantly promoted germination with increasing temperature of treatment from I 5˚C to 20˚C and 30˚C. 3. GA$_3$ treatment enhanced germination in NaOCl-pretreated seeds at early stage of imbibition and in-creased about 10% germination after 10 days of imbibition in KOH-pretreated seeds. 4. NaOC1 treatments significantly decreased the rate of the infection of microflora in seed samples and enhaced emergence of seedlings from soil compared with KOH treatment. 5. NaOC1 treatment had advantage over KOH treatment with respect to ease of preparing, securing and handling in stimulating germinating of Korean lawngrass seeds.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1051-1057
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• 2000

TiO$_2$와 CeO$_2$박막을 Si 위에 증착한 후 MOCVD법에 의해 PbTiO$_3$박막을 증착하여 MFIS 구조를 형성하였다. 절연층의 후열처리가 절연층 및 MFIS 구조의 전기적 특성에 미치는 영향을 관찰하기 위해 산소분위기와 $600^{\circ}C$~90$0^{\circ}C$의 온도범위에서 후 열처리를 행하였고, C-V 특성 및 누설전류 특성을 분석하였다. CeO$_2$와 TiO$_2$박막의 유전상수는 증착 직후 6.9와 15였으며, 90$0^{\circ}C$ 열처리를 행한 후 약 4.9와 8.8로 감소하였다. 누설전류밀도 역시 증착 직후 각각 7$\times$$10^{-5}$ A/$ extrm{cm}^2$와 2.5$\times$$10^{-5}$ A/$\textrm{cm}^2$에서 90$0^{\circ}C$ 열처리를 거친 후에 약 4$\times$$10^{-8}$ A/$\textrm{cm}^2$와 4$\times$$10^{-9}$ A/$\textrm{cm}^2$로 감소하였다. Ellipsometry 시뮬레이션을 통해 계산된 계면층의 두께는 90$0^{\circ}C$에서 약 115$\AA$(CeO$_2$) 및 140$\AA$(TiO$_2$)까지 증가하였다. 계면층은 MFIS 구조에서 강유전층에 인가되는 전계를 감소시켜 항전계를 증가시켰고, charge injection을 방지하여 Al/PbTiO$_3$/CeO$_2$(90$0^{\circ}C$, $O_2$)/Si 구조의 경우 $\pm$2 V~$\pm$10 V의 측정범위에서 memory window가 계속 증가하는 것을 보여주었다.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.309-316
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• 2005

Recently, RFID system is a main technology to realize ubiquitous computing environments, but the feature of the RFID system may bring about various privacy problem. So, many kinds of protocols To resolve this problem are researched. In this paper, we analyse the privacy problem of the previous methods and propose more secure and effective authentication protocol to protect user's privacy. Then we prove that the proposed protocol is secure and effective as we compare the proposed protocol with previous methods. The proposed protocol is based on Challenge-Response using one-way hash function and random number. The proposed protocol is secure against replay attack, spoofing attack and so on. In addition, the proposed protocol is proper for distributed database environment.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.859-864
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• 2006

The openness of the Web allows any user to access almost any type of information easily at any time and anywhere. However, with function of easy access for useful information, internet has dysfunctions of providing users with harmful contents indiscriminately. Some information, such as adult content, is not appropriate for all users, notably children. Additionally for adults, some contents included in abnormal porn sites can do ordinary people's mental health harm. In the meantime, since Internet is a worldwide open network it has a limit to regulate users providing harmful contents through each countrie's national laws or systems. Additionally it is not a desirable way of developing a certain system-specific classification technology for harmful contents, because internet users can contact with them in diverse way, for example, porn sites, harmful spams, or peer-to-peer networks, etc. Therefore, it is being emphasized to research and develop context-based core technologies for classifying harmful contents. In this paper, we propose an efficient text filter for blocking harmful texts of web documents using context-based technologies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.373-384
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• 2014

The social network service is the bidirectional media that many users can build relations not only friends but also other people. However, a process to approach in the social network is so simple that untrustable information, which malignant users make, is spreaded rapidly in many the social network uses. This causes many users to suffer material or psychological damages. Because of openness in the social network, there will be higher risk of the privacy invasion. Therefore, sensitive information should be transferred or provided only to reliable users. In general, because many users exchange among one hops, many researches have focused on one hop's trust evaluation. However, exchanges between users happen not only one joint bridege but also far nodes more than two nodes on account of dense network and openness. In this paper we propose the efficient scheme combining transitivity and composability for remote users.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.157-168
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• 2005

Group key agreement protocols are designed to provide a group of parties securely communicating over a public network with a session key. The mobile computing architecture is asymmetric in the sense of computational capabilities of participants. That is, the protocol participants consist of the stationary server(application servers) with sufficient computational Power and a cluster of mobile devices(clients) with limited computational resources. It is desirable to minimize the amount of computation performed by each group member in a group involving low-power mobile devices such as smart cards or personal digital assistants(PDAs). Furthermore we are required to update the group key with low computational costs when the members need to be excluded from the group or multiple new members need to be brought into an existing group. In this paper, we propose a dynamic group key protocol which offers computational efficiency to the clients with low-power mobile devices. We compare the total communicative and computational costs of our protocol with others and prove its suity against a passive adversary in the random oracle model.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3597-3605
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• 1999

We introduce a new satellite Conditional Access System(CAS) that a subscriber could watch a pay-TV knowing only his or her identity and password, without using a smart card. For this new system, two password-based protocols are presented which not only share a session key and authenticate each other but also download an authorization key. This system has some merits: First, compared with current systems, it reduces the amount of computations by eliminating the AK-encryption module in SMS(Subscriber Management System) and simplifying the receiver's CW-decryption process. Second, since this system does not need an expensive Card Adaptive Device(CAD), it can reduce costs. finally it provides descrambler independence allowing it to be used through any TV set-top box that includes a descrambler, unlike the current system that a descrambler is linked with a smart card.

• Radiation Oncology Journal
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• v.9 no.2
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• pp.227-232
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• 1991

Authors described the remote afterloading endobronchial brachytherapy (EBBT technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were emploiyed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.400-400
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• 2010

우리는 기본 진공 $10^{-11}\;Torr$의 UHV surface magneto-optical Kerr effect (SMOKE) 시스템을 quarter-wave plate를 사용하였던 기존의 방식에서 PEM (photo elastic modulator)를 사용하는 방식으로 장비의 기능을 향상시켰다. 기존 quarter-wave plate를 사용하는 방식의 경우 Kerr signal을 구하기 위해 편광자와 검광자를 수직으로 두어 광량을 0으로 만들어야 한다. 그러나 금속의 경우 대부분 가시광선 영역에서 큰 반사율 때문에 측정되는 광량이 편광자와 검광자를 거치면서 넓은 각도 범위에서 최소값을 갖기 때문에 정확한 영점을 잡는 데 한계가 있다. 이러한 단점을 해결하기 위하여 우리는 PEM을 이용한 위상변조방식을 사용하였다. 위상변조 방식은 Kerr signal과 관계된 양을 PEM을 이용하여 50 kH ($1{\omega}$)와 100 kH ($2{\omega}$)의 진동 주파수에 공조시키고 이를 Lock-in-amplifier를 사용하여 탐지하기 때문에 좋은 sensitivity를 얻을 수 있을 뿐 아니라 Kerr ellipticity와 Kerr rotation을 동시에 측정할 수 있다. 자화에 필요한 전자석은 순철로 된 코어를 제작하여 챔버에 부착하였고 10 A에서 최대 7 kOe의 고자장을 얻을 수 있어 포화자화가 큰 물질에 대해서도 필요한 자성영역까지 측정이 가능하게 하였다. 또 저온 측정을 위해 SMOKE 샘플 홀더를 개조하여 액체 질소를 이용하여 100 K 근방의 영역에서 온도를 제어할 수 있도록 저온 장치를 구성하였다. 여기에서 샘플 근처에 위차한 e-beam heater가 장착된 고온 부분과 액체 질소 냉각, 온도감지를 위한 센서, cartridge heater가 장착된 저온 부분을 sapphire plate로 분리하여 저온용 cartridge heater의 파손을 최소화하였다. 이러한 SMOKE 시스템을 구성한 후에 우리는 Fe/Cr(001)시스템의 자성특성에 대해 연구하였다. Fe/Cr 시스템은 Fe/Cr/Fe의 exchange coupling이나 bulk Cr의 복잡한 자성 특성 때문에 주목을 받아왔다. 이 연구에서 우리는 저온 및 상온에서 Cr(001) 단결정 위에 증착된 Fe 박막의 자성 특성을 보고한다.