• Communications of Mathematical Education
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• v.25 no.4
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• pp.653-679
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• 2011

The objective of this study is to develop university-level program(UP) 'Statistics Curriculum'. The UP program is a Korean curriculum sponsored by the Ministry of Education and Technology, which offers standardized courses to high school students that are generally recognized to be equivalent to undergraduate courses in college. In this paper we analyze that various programs are being conducted currently in Korea and overseas related with University-level Program in mathematics. And we describe course of the study, mathematical objectives of developed statistics curriculum on the study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.388-394
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• 2008

In this paper, MAC(Medium Access Control) algorithm for the IEEE 802.11 DCF(Distributed Coordination Function) improving the performance is proposed and analyzed by simulation. The MAC of IEEE 802.11 WLAN to control data transmission uses two control methods called DCF and PCF(Point Coordination function). The DCF controls the transmission based on CSMA/CA(Carrier Sense Multiple Access With Collision Avoidance). The DCF shows excellent performance relatively in situation that competition station is less but has a problem that performance is fallen from throughput and delay viewpoint in situation that competition station is increased. This paper proposes an enhanced DCF algorithm that increases the CW to maximal CW after collision and decreases the CW smoothly after successful transmission in order to reduce the collision probability by utilizing the current status information of WLAN. To prove efficiency of proposed algorithm, a lots of simulations are conducted and analyzed.

• Korean Journal of Logic
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• v.17 no.1
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• pp.109-136
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• 2014

Every (semantic) antirealist accepts one or another form of verification principle. The principle has strong and weak forms, the strong form being highly counterintuitive but the weak one being more plausible. Understandably, antirealists have preferred the weak form of verification principle. Unfortunately, the socalled knowability paradox shows that those two forms are indeed equivalent. To solve this problem, Edgington suggests a yet new form of verification principle. Unfortunately, her new principle has its own difficulty. To overcome this difficulty, Edgington provides a new model of knowledge, according to which every true proposition is somehow associated with a known counterfactual conditional. In this paper, I shall argue that even this new model of knowledge confronts with an insurmountable problem. It is a well-known fact that, in the microscopic levels, some facts manage to occur despite very low physical chances. I will argue that the counterfactuals linked with those facts cannot be known due to the existence of epistemic defeaters. Hence, Edgington's knowledge model does not work in all cases.

• Journal of KIISE:Software and Applications
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• v.32 no.11
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• pp.1071-1083
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• 2005

By estimating probability distributions of the good solutions in the current population, some researchers try to find the optimal solution more efficiently. Particularly, finite mixtures of distributions have a very useful role in dealing with complex problems. However, it is difficult to choose the number of components in the mixture models and merge superior partial solutions represented by each component. In this paper, we propose a new continuous evolutionary optimization algorithm with distribution estimation by variational Bayesian mixtures of factor analyzers. This technique can estimate the number of mixtures automatically and combine good sub-solutions by sampling new individuals with the latent variables. In a comparison with two probabilistic model-based evolutionary algorithms, the proposed scheme achieves superior performance on the traditional benchmark function optimization. We also successfully estimate the parameters of S-system for the dynamic modeling of biochemical networks.

• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.542-553
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• 2005

Recommendation systems analyze user preferences and recommend items to a user by predicting the user's preference for those items. Among various kinds of recommendation methods, collaborative filtering(CF) has been widely used and successfully applied to practical applications. However, collaborative filtering has two inherent problems: data sparseness and the cold-start problems. If there are few known preferences for a user, it is difficult to find many similar users, and therefore the performance of recommendation is degraded. This problem is more serious when a new user is first using the system. In this paper we propose a method of integrating additional feature information of users and items into CF to overcome the difficulties caused by sparseness and improve the accuracy of recommendation. In our method, we first fill in unknown preference values by using the probability distribution of feature values, then generate the top-N recommendations by applying collaborative filtering on the modified data. We call this method of filling unknown preference values as data blurring. Several experimental results that show the effectiveness of the proposed method are also presented.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.233-240
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• 2016

Information system development projects, have a mechanism for many of the costs generated by a variety of risk factors. In general, the probability that the software project of the information system is carried out successfully in the delivery time is very low. This prediction of a formal cost is needed as the most important factor since it can prevent the project from being failed. However, objectivity of most of the project scale calculation during the calculation criteria is insufficient. Further, it is the actual situation that the management of the base line is not properly made during the project. Therefore, in this paper, we propose a model to calculate the number of steps it takes to develop on the basis of a methodology in an attempt to overcome the limitation of being unpractical in the early stage of the information system development project. It is expected to be a tool to estimate the effort and cost required by the information system development business through these convergence proposals model.

• Korean Journal of Acupuncture
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• v.24 no.1
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• pp.13-25
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• 2007

목 적 : 흡연에 따른 건강적 피해가 많이 알려져 있음에도 불구하고 특히 여성 및 청소년 계층의 흡연이 증가하고 있으며 폐암 사망자수는 급격히 늘어나고 있는 상황이다. 완전한 금연이 실패하는 주요 이유는 담배의 중독성에서 비롯되며 금단현상을 극복하지 못해 일어나는 것으로 알려져 있다. 흡연의 중독성은 담배 주요성분 중의 하나인 니코틴(nicotine)에 의해 유발되며 따라서 모든 금연 요법 및 금연 치료보조제 들은 이 니코틴 작용을 어떻게 효과적으로 억제 또는 대체하느냐에 초점을 맞추고 있다. 최근 금연치료 요법으로 한방 침이 주목 받고 있으며 본 논문을 통해 한방 침의 금연효과에 대한 신경학적 기전을 고찰하고자 한다. 방 법 : 금연을 돕는 전형적인 보조 치료제 및 치료법이 몇 종류 개발되어 사용 중에 있으며 대표적으로 니코틴 대체 요법(nicotine replacement therapy, NRT)이나 항우울제로 사용되는 bupropion 등을 들 수 있다. 이 치료 방법들은 뇌의 도파민계 신경전달 체계에 영향을 미쳐 금연 효과를 발휘하게 되는데 실질적인 금연성공확률은 그리 높지 않은 것으로 알려져 있다 따라서 침의 자극에 대한 도파민계 신경전달 조절효과를 중심으로 고찰함으로써 침의 금연효과에 대한 의과학적 기전을 설명하고자 하였다. 결 과 : 침자극은 우수한 금연효과를 가져올 수 있는 치료법으로 기존의 금연 치료요법 및 치료제 들을 보완할 수 있는 보다 확실한 치료요법 중의 하나이며 특히 금연 후에 오는 금단현상을 효과적으로 완화시키는 작용을 한다. 그리고 이 같은 효과는 부분적으로 도파민계를 비롯한 신경전달계를 조절함으로써 가능한 것으로 판단된다. 결 론 : 본 논문을 통해 니코틴에 의한 금단현상의 신경학적 기전과 금연과 관련된 신경전달체계에 대한 침자극의 효능에 대해 고찰하였으며 기존의 금연보조치료법을 대체할 수 있는 우수한 의학적 치료법으로써의 침치료법을 제시하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.10 s.340
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• pp.39-50
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• 2005

In this paper, we propose a performance improving MAC algerian for the IEEE 802.11 DCF. WLAN based IEEE 802.11 uses two control methods called 'Distributed Coordination Function(UF)' and 'Point Coordination Function(PCF)'. The nF controls the Urnsmission based on carrier sense multiple access with collision detection(CSMA/CA), that decides a random backoff time with the range of contention window for each terminal. Normally, each terminal the CW double after collision, and reduces the CW to the minimum after successful transmission. This paper proposes an enhanced DCF algorithm that decreases the CW smoothly after successful transmission in order to reduce the collision Probability by utilizing the current status information of WLAN. We also analyze the throughput and delay performance for the unsaturated case mathematically. Simulation results show that our algorithm enhances the saturation throughput of WLAN. They also coincide well with the analytical results.

• Journal of Korean Biological Nursing Science
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• v.22 no.3
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• pp.176-183
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• 2020

Purpose: : The purpose of this study was to evaluate the intrauterine insemination (IUI) success rate and to define the variables for predicting success. Methods: The secondary data analysis was used with data collected from infertile females who underwent IUI in Fertility and IVF (In Vitro Fertilization) clinics, who benefited from the 'National Medical-aid Program for ART (assisted reproductive technology) in 2016', in which the data of 34,920 IUI cases were retrospectively reviewed. The primary outcome measure was the clinical pregnancy rate in elderly and young infertile females. Data were analyzed by descriptive statistics, χ2 test and logistic regression. Results: The pregnancy rate was 12.1% (2,095 cases) in elderly infertile females and 15.6% in young infertile females (2,758 cases) (χ2 = 87.90, p< .001). Using the logistic regression analysis, clinical pregnancy was positively associated with the ovulatory factor (OR= 1.48, p< .001) and male factor (OR= 1.19, p< .05) in elderly infertile females. It was positively associated with the ovulatory factor (OR= 1.30, p= .001) and the peritoneal cavity factor (OR= 0.58, p< .05) in young infertile females. Conclusion: Our results indicate that the pregnancy rate in young infertile females was higher than that in old infertile females, and the IUI is the effective option in pregnancies in all ages with infertility due to the ovulatory factor. Additionally, further studies are necessary to fully describe pregnancy experiences for all the infertile females.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.501-507
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• 2015

The online banking service handles a banking business over the internet, it is necessary to ensure that all financial transactions are processed securely. So, there are various authentication technique for e-banking service : a certificate, a personal identification number(PIN), a security card and a one-time password(OTP). Especially, the security card is most important means including secret information. If the secret information of card is leaked, it means not only loss of security but also easy to attack because security card is a difficult method to get. In this paper, we propose that a multi-channel security card saves an secret information in distributed channel. Proposed multi-channel security card reduces vulnerability of the exposed and has a function to prevent phishing attacks through decreasing the amount of information displayed and generating secret number randomly.