• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.795-800
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• 2012

Recently, as communication is evolved by leaps and bounds through wired/wireless networks, variety of services are routinely made through communication networks. Accordingly, technology that is for protecting data and personal information is required essentially, and study of security technology is actively being make progress to solve these information protection problems. In this paper, to expand selection scope of the key of elliptic curve cryptography, arithmetic items of real number based elliptic curve algorithm among various cryptographic algorithms was studied. The result of an experiment, we could know that elliptic curve cryptography using the real number can choose more various keys than existing elliptic curve cryptography using integer and implement securer cryptographic system.

• Journal of applied mathematics & informatics
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• v.20 no.1_2
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• pp.35-59
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• 2006

In this paper, we generalized the results of [23, 26], and get the results of the condition number of the W-weighted Drazin-inverse solution of linear system W AW\chi=b, where A is an $m{\times}n$ rank-deficient matrix and the index of A W is $k_1$, the index of W A is $k_2$, b is a real vector of size n in the range of $(WA)^{k_2}$, $\chi$ is a real vector of size m in the range of $(AW)^{k_1}$. Let $\alpha$ and $\beta$ be two positive real numbers, when we consider the weighted Frobenius norm $\|[{\alpha}W\;AW,\;{\beta}b]\|$(equation omitted) on the data we get the formula of condition number of the W-weighted Drazin-inverse solution of linear system. For the normwise condition number, the sensitivity of the relative condition number itself is studied, and the componentwise perturbation is also investigated.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.1
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• pp.169-176
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• 2010

Let $k={\mathbb{F}}_q(T)$ and ${\mathbb{A}}={\mathbb{F}}_q[T]$. In this paper, we obtain the the criterion for the parity of the ideal class number h(${\mathcal{O}}_K$) of the real biquadratic function field $K=k(\sqrt{P_1},\;\sqrt{P_2})$, where $P_1$, $P_2{\in}{\mathbb{A}}$ be two distinct monic primes of even degree.

• Journal of fish pathology
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• v.31 no.2
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• pp.101-107
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• 2018

Quantitative analysis of a myxosporean parasite, Parvicapsula sp. in internal organs (kidney, intestine, spleen, brain and liver) from non-emaciated (farm-A) or emaciated (farm-B and farm-C) olive flounder Paralichthys olivaceus were performed by real-time PCR. The highest DNA copy number ($1.7{\times}10^7copies/mg$ tissue) was detected in kidney of the emaciated olive flounder from farm-C, while the DNA copy number was below detection limit in all the organs of the olive flounder from farm-B. There was not positive result in all of organs from olive flounder in farm-A. PCR and histopathological analysis were also performed using the same specimen and showed same results as those by real-time PCR.

• School Mathematics
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• v.16 no.3
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• pp.491-502
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• 2014

This paper analyzed pre-service teachers' justification of $0.99{\cdots}$=1 from their disproof of $0.99{\cdots}$ <1. Some pre-service teachers thought of the difference between $0.99{\cdots}$ and 1 as an infinitesimal. On the contrary, the others claimed that the difference between $0.99{\cdots}$ and 1 was zero as the standard real, but were content with their intuitive justifications. The pre-service teachers' limitation revealed in the process of disproving $0.99{\cdots}$ <1 can be closely related to the orthodox view: the standard real number system is the only absolutely true number system. The existence of nonstandard real number system in which $0.99{\cdots}$ is less than 1, shows that the plain question of whether or not $0.99{\cdots}$ equals 1, cannot be properly answered by common explanations of textbooks or teachers' intuitive justification.

• Education of Primary School Mathematics
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• v.25 no.2
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• pp.197-211
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• 2022

In this study, we tried to find a way to improve the pedagogical decision-making practices related to the presentation order of 'large number' and 'small number' in problem situations of subtraction of the natural number. For this purpose, the elementary school teachers' perception about problem situations in real-life context of subtraction of natural numbers was investigated, and the collected data were analyzed qualitatively and quantitatively to identify teachers' pedagogical perceptions. As a result of this study, it was confirmed the need for consideration on how to set up a problem situations in real-life context of subtraction so that students can develop their ability to solve various types of problems. To this end, not only in a problem situation of subtraction where you have to think of 'large number' first and 'small number' later, but also about the introduction of problem situations in real-life context of subtraction in which you think about 'small number' first and 'large number' later, which often appears in real-life. You will need to recognize the need. And you should have a pedagogical view on this. The results of this study will be able to contribute to the preparation of pedagogical method that can expand the understanding of various problem situations where subtraction is applied from the lower grades of elementary school.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2101-2105
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• 2003

Recently the number of Internet users has very sharply increased, and the number of intrusions has also increased very much. Consequently, security products are being developed and adapted to prevent systems and networks from being hacked and intruded. Even if security products are adapted, however, hackers can still attack a system and get a special authorization because the security products cannot prevent a system and network from every instance of hacking and intrusion. Therefore, the researchers have focused on an active hacking prevention method, and they have tried to develop a traceback system that can find the real location of an attacker. At present, however, because of the characteristics of Internet - diversity, anonymity - the real-time traceback is very difficult. To over-come this problem the Network-based Real-Time Connection Traceback System (NRCTS) was proposed. But there is a security problem that the victim system can be hacked during the traceback. So, in this paper, we propose modified NRCTS with connection redirection technique. We call this traceback system as Connection Redirected Network-based Real-Time Connection Traceback System (CR-NRCTS).

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.291-296
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• 2008

Wireless network technologies are becoming more widely used in industrial environment. The industrial communication system requires a real-time delivery of messages. The sensors periodically senses the physical environment and wants to deliver the data in real-time to the sink. This paper proposes a real-time protocol for periodic messages on wireless sensor and actor networks to be used in industrial communications. The proposed protocol delivers the data message using the shortest path from the source and the nearest actor. The protocol considers the energy consumption by reducing the number of broadcast messages during flooding. We have evaluated the performance of the proposed protocol using QualNet simulator. The simulation results show that the data messages have been delivered in real-time and the number of broadcast messages is reduced from 90% to 35% compared the existing protocols.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.274-280
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• 2008

To investigate the flexural behavior of real size RC beams strengthened with glass fiber sheets, 9 strengthened beams of real size are experimented and the results are compared with those of existing experimental studies. Experiments are considered glass fiber sheets, the number of fiber sheets, and the existence of U-wrap. By the results of experiments, the failure behavior and crack types of real size RC beams are almost equal to those of the small size RC beams, and the debonding and not the concrete cover delamination are occurred. It can be found from the load-deflection curves that as the number of fiber sheets is increased, the ductility of real size RC beam is more decreased than that of the small size RC beam. For the strengthening method with glass fiber sheets of the real size RC beams, it can be confirmed that the finding a solution to the bonding problem is required

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.125-131
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• 1999

In this paper, we address practical methods for calculating camera lens distortion for real time applications. Although the lens distortion problem can be easily ignored for constant-parameter lenses, in the field of real-time camera calibrations, for zoom lenses a large number of calculations are needed to calculate the distortion. However, if the distortion can be calculated independently of the other camera parameter, we can easily calibrate a camera without the need for a large number of calculations. Based on Tsai's camera model, we propose two different methods for calculating lens distortion. These methods are so simple and require so few calculations that the lens distortion can be rapidly calculated even in real-time applications. The first method is to refer to the focal length - lens distortion Look Up Table(LUT), which is constructed in the initialization process. The second method is to use the relationship between the feature points found in the image. Experiments were carried out for both methods, results of which show that the proposed methods are favorably comparable in performance with non-real full optimization method.