• Communications for Statistical Applications and Methods
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• v.15 no.4
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• pp.563-585
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• 2008

This paper presents how to improve the efficiency and accuracy in the pricing and sensitivity evaluation for derivatives, since the need for the evaluation of complicated derivatives is increased. The Monte Carlo(MC) simulation using the quasi random number instead of pseudo random number can improve the elapsed time and accuracy for the valuation of European-type derivatives. However, the quasi MC simulation method has its limit for applying it in the multi-dimensional case such as American-type and path-dependent options due to the increased correlation between dimensions as the dimension of random numbers is increased. In order to complement this problem, we develop a modified method in which correlation values are controlled to be below a pre-specified value. Thus, this method is applicable for the pricing of either derivatives ill which underlying assets or risk factors are several or derivatives having path-dependent or early redemption property. Furthermore, we illustrate that it is important to take an appropriate grid interval for the use of finite difference method(FDM) by applying the FDM to one example of non-symmetrical butterfly spreads.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.936-944
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• 2006

In order to enhance their own customer satisfaction index that is one of the top level managerial performance indices, Internet communication service providers endeavor onto establishing a total quality management system. Specifically, it is under discussion that some critical Internet communication network quality characteristics closely related to customer satisfaction index should be controlled aiming to this managerial goal. This paper presents an application scheme of I-MR control charts for monitoring Internet communication network quality characteristics. This statistical quality control scheme generates a signal to practitioners when it detects the network quality characteristics out-of control. It is designed based on; 1) individual measurements; and 2) moving ranges between two consecutive individual measurements collected with a constant time interval. Empirical analyses are illustrated to estimate the expected quality improvement ratios that can be realized with the application scheme proposed in this paper. Assuming that the assignable causes can be revealed and eradicated, regarding two Internet communication services A, B, seven network quality characteristics for each service, eleven distinct measuring spots for each network quality characteristic, the expected quality improvement ratios are calculated with which the effect of the application scheme is evaluated. Results show the ranges of the expected quality improvement ratios; 1) Service A, (1) mean (0.31%-11.44%), (2) standard deviation (9.82%-71.10%): 2) Service B, (1) mean (0.29%-17.64%), (2) standard deviation (8.05%-60.59%). Hence, It is anticipated that the I-MR control charts based application scheme can be effective not only to improving the mean and dispersion of the network quality characteristics concerned but also to maintaining the network quality characteristics in-control consequently.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.457-463
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• 2012

The basilar membrane (BM), one of organs of cochlea, has the specific positions of the maximum amplitude at each of related frequencies. This phenomenon is due to the geometry of BM. In this study, as the part of the research for the development of fully implantable artificial cochlea which is based on polymer membrane, parametric studies are performed to suggest the desirable artificial basilar membrane model which can detect wider range of frequency separation. The vibro-acoustic characteristics of the artificial basilar membrane are predicted through finite element analysis using commercial software Abaqus. Simulation results are verified by comparing with experimental results. Various geometric shapes of the BM and residual stress effects on the BM are investigated through the parametric study to enable a wider detectable frequency separation range.

• Journal of Life Science
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• v.23 no.8
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• pp.1041-1049
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• 2013

The root of Polygala radix has been widely known as an oriental traditional medicinal stuff that improves memory. However, its mechanism of action remains unclear. In this study, the effect of Polygala radix hot water extracts (PRHWE) on cognitive function related to the activity of acetylcholinesterase (AchE) derived from neural cells (PC12) in addition to antioxidant activity was examined both in a cell-free system and live cells. First, in the study on cell viability using an MTT assay, PRHWE did not exhibit any cell toxicity at 0.1% (w/v) or below. It also was observed that PRHWE increased the scavenging activity of DPPH radical, hydrogen peroxide and superoxide, reducing power in a dose-dependent manner. In particular, PRHWE had a protective effect on DNA oxidation induced by hydroxyl radicals. Additionally, it inhibited the production of inducible nitric oxide in neuronal cells. Furthermore, the AchE activity decreased with increasing concentrations. In addition, PRHWE increased the expression level of SOD-1 and NOS-2 in PC12 cells. Moreover, the transcriptional activities of p53 and NF-${\kappa}B$ were reduced in the presence of PRHWE in an experiment using a reporter gene assay. Therefore, these results prove that PRHE has antioxidative and protective effects on neuronal cells, suggesting that it may have great potential as a therapeutic agent for human health.

• Communications of Mathematical Education
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• v.29 no.1
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• pp.111-130
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• 2015

The purpose of the study was to investigate the differences between two groups of students according to information recognition styles such as visual learners and linguistic learners. Two instructional methods, algeblocks and factorization formula, were utilized to introduce the factorization. Four students were participated for the study, and two of them were visual learners and the other two were linguistic learners based on learning style test. Interviews and the diagnostic tests were implemented before the instructions which were lasted for 6 sessions. After the instructions all the participants were interviewed and the researchers also interviewed them 5 days later. The results of the study were the followings: 1. All the participants regardless of their learning style revealed that algeblocks were helpful in understanding the factorization. 2. Visual learners were more likely using algeblocks, while the linguistic learners were more enthusiastic and proficient in using formula to solve the problems. 3. Five days later, two types of learning style students revealed different tendencies. Visual learners mainly used algeblocks, and linguistic learners were not enthusiastic about using algeblocks and one of them did not use them at all. 4. Five days later, two visual learners could not remember the formula, but linguistic learners could remember the formula in somewhat different level.

• Fire Science and Engineering
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• v.32 no.4
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• pp.25-34
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• 2018

This study investigated the development of a fire alarm system with evacuation lighting and voice alarm functions. The performance of a fire detector and system with independently built-in evacuation lighting and voice alarm functions was confirmed for early recognition of fire and to allow visibility of the evacuation route in the event of fire. This new system satisfied model recognition and product testing technological standards with 1.62 lx average illumination, 89.7 dB average sound and 86.1 dB average voice. From additionally testing the evacuation performance of this new system, it was confirmed that the evacuation time decreased by 63.08% to 67.82% under the experimental conditions compared to conventional systems. The new system can minimize fire damage by setting off voice alarms to prevent failure of fire recognition and by flashing emergency lighting to secure the minimum required visibility range for evacuation. Therefore, it is considered that it will be utilized as a fire alarm system with appropriateness and usefulness by considering people with hearing or visual impairment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.385-410
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• 2016

The disposal facility in Gyeongju is planning to dispose of 800,000 packages of low- and intermediate- level radioactive waste. This facility will be developed as a complex disposal facility that has various types of disposal facilities and accompanying management. In this study, based on the comprehensive development plan of the disposal facility, a preliminary post-closure safety assessment is performed to predict the phase development of the total capacity for the 800,000 packages to be disposed of at the site. The results for each scenario meet the performance target of the disposal facility. The assessment revealed that there is a significant impact of the inventory of intermediate-level radionuclide waste on the safety evaluation. Due to this finding, we introduce a disposal limit value for intermediate-level radioactive waste. With stepwise development of safety case, this development plan will increase the safety of disposal facilities by reducing uncertainties within the future development of the underground silo disposal facilities.

• Journal of Technology Innovation
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• v.22 no.3
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• pp.225-260
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• 2014

In this paper, we present a literature review of the mechanisms and methodology for technology spillover, in order to provide a theoretical and practical foundation for estimating the technology spillover effect of public funded R&D programs. Our research consists of four parts. First, we investigate what technology spillover is and how it works. Second, we review the methodology used to empirically measure technology spillover, with a view to understanding the advantages and disadvantages of each method. Third, we identify the gap between the spillover phenomenon and its estimated results, caused by the limitations of the methodology, and discuss the challenges in measuring technology spillover. Finally, we present several considerations to improve the measurement of technology spillover in the context of public funded R&D programs. Our paper provides policy makers and researchers with basic knowledge about technology spillover and helps them suitably evaluate the results obtained from the literature review. In addition, it contributes towards improving the existing methodology by recognizing the gap between the spillover phenomenon and the methodology.

• Land and Housing Review
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• v.7 no.2
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• pp.77-85
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• 2016

The government has switched the purpose of housing policy, from the 'housing supply' to 'housing welfare', with the Housing Laws established in 2015 under evaluation that resident stability and resident standard were improved. But, as 'affordable' housing is gradually decreasing, residential environment has become more poor. Residential environment is a basic element for the child safety, health, and better education. This study explored that the poor resident environment had effect on the child, figured out the situation on housing poverty of domestic child and searched the situation of the residential policy of domestic and foreign child. The main results are as follows. First, the poor resident environment of childhood has a bad effect on the physical health, mental health, academic achievement and cognitive development. Second, 1.29 million children (11.9%) are living in condition of housing poverty below minimum resident standard and are concentrated in certain areas. Third, the policy on housing poverty of domestic child is almost absent and focuses on the elderly, young people. this study discussed political and practical solutions based on these research results. On the basis of these research results, as policy suggestions we proposed housing policy making based on the UN Convention on the Rights of the Child, evidence-based housing policy enforcement and, residential policy suggestions under the responsibility of central government, and as practical suggestions community working as the subject and related agency's solidarity from prevention activity of housing poverty and child advocacy point and we discussed way for issue and analyzed related laws, policies, commitments.

• Journal of Science Education
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• v.34 no.2
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• pp.359-368
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• 2010

The purpose of this study was to find out the factor that causes the difference on understanding the aim and perception of laboratory activities between teachers and students. For this study, in-depth interview was conducted for sixth grade students and teachers of 10 classes. The questionnaire of the interview can be divided into 3 sections: the aim of laboratory activities, whether teachers present the aim of laboratory activities, the method of laboratory class progress and the evaluation method. The factors that bring about the difference between the teachers and the students on perception of the aim are the absence of proper guidance on the aim of laboratory activities, the laboratory classes that the progress out of teachers' intention and evaluation method that is the performed without any relationship with the aim of the laboratory activities. Because the teacher-intended aim of laboratory activities is not properly presented, students can't percept the accurate aim. Even though teachers recognize the importance of the improvement of science process skill acquired through laboratory activities, this is not delivered practically in the class and students also can't percept the importance of science process skill.