• Bulletin of the Korean Mathematical Society
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• v.51 no.2
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• pp.457-478
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• 2014

In this paper, a 3D autonomous system, which has only stable or non-hyperbolic equilibria but still generates chaos, is presented. This system is topologically non-equivalent to the original Lorenz system and all Lorenz-type systems. This motivates us to further study some of its dynamical behaviors, such as the local stability of equilibrium points, the Lyapunov exponent, the dissipativity, the chaotic waveform in time domain, the continuous frequency spectrum, the Poincar$\acute{e}$ map and the forming mechanism for compound structure of its special cases. Especially, with the help of the Project Method, its Hopf bifurcation of codimension one is in detailed formulated. Numerical simulation results not only examine the corresponding theoretical analytical results, but also show that this system possesses abundant and complex dynamical properties not solved theoretically, which need further attention.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.111-116
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• 2001

This paper introduces how to adopt the X-12-ARIMA to decompose the railway passenger demand of the Korea National Railroad Especially, selecting on proper filters is focused. The trend filter is identical to the low pass filter in the signal Processing field, and so the seasonal filter is to band pass filter too. Some considerations, selecting a filter, are provided from the view-point of the spectrum analysis. The technique introduced in this paper will be adopted to the project that is to develope the forecasting system of Korea railway passenger demand which is a part of the high speed rail information system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1106-1112
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• 2009

The SC-FDMA(single carrier-frequency division multiple access) was recently adopted as the uplink multiple access scheme from 3GPP LTE(3rd Generation Partnership Project Long Tenn Evolution) due to its low PAPR (Peak-to-averaged power ratio). The bandwidth of IFDMA(interleaved FDMA), one of the sub-carrier mapping methods of SC-FDMA, gets narrower as the roll-off factor of RRC(root raised cosine) filter decreases from 1 to 0, whereas its PAPR can increase significantly. In practice, to increase the power efficiency of an amplifier, signals with high PAPR undergo the process of clipping. Clipping of signals may cause regeneration of high-frequency components as well as distortion of signals. The current paper deals with the effect of clipping on the spectrum and BER of IFDMA signals with RRC filters.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.105-112
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• 2005

Obiective : The purpose of this study was to assess the effect of acupuncture treatment for chronic headache patients using power spectrum analysis of the heart rate variability(HRV). Methods : 15 clinical experiment participants were gathered and through a questionnaire patients who experienced headache for more than 4 hours a day and more than IS days per month were qualified as Chronic Headache patients. Treatment was afplied 2 times a weeks for 8 weeks. The acupoints, GV2O, HN23, ST8, HN46, TEl7, GB2O, LI2O, LI11, LI14, ST36, and LR3 were stimulated for 20 minutes. The effects of acupuncture treatment were analyzed using power spectrum analysis of the HRV. HRV was recorded before and after acupuncture treatment. Results : HRV before and after treatment was compared after 8 weeks of acupuncture treatment. Increase in mean values of SDNN and RMSSD were observed but the increases were not statistically significant. Increase in mean values of TP, LF and HF were observed but, the increase was significant(p<0.05) only in TP. Conclusions : The results suggest that acupuncture treatment on chronic headache patients can increase the activity of autonomic nervous system. Further use of HRV for quantitative analysis of acupuncture treatment on autonomic nervous system related symptoms is suggested.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2717-2724
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• 2020

Silicon, especially silicon in the form of SiO₂, is a major component of rocks. Final spent fuel storages, which are being designed, are located in suitable rock formations in the Earth's crust. Reduction of the uncertainty of silicon neutron scattering and capture is needed; improved silicon evaluations have been recently produced by the ORNL/IAEA collaboration within the INDEN project. This paper deals with the nuclear data validation of that evaluation performed at the LR-0 reactor by means of critical experiments and measurement of reaction rates. Large amounts of silicon were used both as pure crystalline silicon and SiO₂ sand. The critical moderator level was measured for various core configurations. Reaction rates were determined in the largest core configuration. Simulations of the experimental setup were performed using the MCNP6.2 code. The obtained results show the improvement in silicon cross-sections in the INDEN evaluations compared to existing evaluations in major libraries. The new Thermal Scattering Law for SiO₂ published in ENDF/B-VIII.0 additionally reduces the discrepancy between calculation and experiments. However, an unphysical peak is visible in the neutron spectrum in SiO₂ obtained by calculation with the new Thermal Scattering Law.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.959-966
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• 2013

In this study, based on P-3CK project using aging aircraft without any design information, the structural assessments of fastener holes to repair the short edge distance defects are investigated. For this purpose, the nacelle longeron which has many defects is selected and then conservative stress is calculated by performing the static analysis of 1.5ED, 1.8ED, 2.0ED defects of longeron fastener holes. This result applies to TWIST standard load spectrum to generate flight load spectrum. Then the crack growth analysis is performed by using flight load spectrum. Through this, the validity of a repaired fastener hole is evaluated. Finally, the standard of repair and the period of maintenance for a defected fastener hole are established.

• Parasites, Hosts and Diseases
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• v.48 no.4
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• pp.285-290
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• 2010

Tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. However, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by Entamoeba histolytica, In this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. Entamoeba-induced receptor shedding of CD16 and PS externalization in neutrophils were inhibited by pre-incubation of neutrophils with the broad-spectrum tyrosine kinase inhibitor genistein or the Src family kinase inhibitor PP2. Entamoeba-induced ROS production was also inhibited by genistein or PP2, Moreover, genistein and PP2 blocked the phosphorylation of ERK and p38 MAPK in neutrophils induced by E. histolytica. These results suggest that Src tyrosine kinases may participate in the signaling event for ROS-dependent activation of MAPKs during neutrophil apoptosis induced by E. histolytica.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.184-188
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• 2013

In the continued search for inhibitors of enoyl-acyl carrier protein (ACP) reductase, we found that four acylbenzenediol sulfate metabolites from Streptomyces sp. AN1761 potently inhibited bacterial enoyl-ACP reductases of Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium tuberculosis. Their structures were identified as panosialins A, B, wA, and wB by MS and NMR data. They showed stronger inhibition against S. aureus FabI and S. pneumoniae FabK with $IC_{50}$ of 3-5 ${\mu}M$ than M. tuberculosis InhA with $IC_{50}$ of 9-12 ${\mu}M$. They also exhibited a stronger antibacterial spectrum on S. aureus and S. pneumoniae than M. tuberculosis. In addition, the higher inhibitory activity of panosialin wB than panosialin B on fatty acid biosynthesis was consistent with that on bacterial growth, suggesting that they could exert their antibacterial activity by inhibiting fatty acid synthesis.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.765-774
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• 2009

For over 30 years, investigations of the thermohydraulic behavior of pressurized-water reactors under accident conditions have been carried out in the PKL test facility at AREVA NP in Erlangen, Germany. The PKL facility models the entire primary side and significant parts of the secondary side of a of pressurized water reactor at a height scale of 1:1. Volumes, power ratings and mass flows are scaled with a ratio of 1:145. The experimental facility consists of four primary loops with circulation pumps and steam generators (SGs) arranged symmetrically around the reactor pressure vessel (RPV). The investigations carried out encompass a very broad spectrum from accident scenario simulations with large, medium, and small breaks, over the investigation of shutdown procedures after a wide variety of accidents, to the systematic investigation of complex thermohydraulic phenomena. The PKL tests began in the mid 1970s with the support of the German Research Ministry. Since the mid 1980s, the project has also been significantly supported by the German PWR operators. Since 2001, 25 partner organizations from 15 countries have taken part in the PKL investigations with the support and mediation of the OECD/ NEA (Nuclear Energy Agency). After an overview of PKL history and a short description of the facility, this paper focuses on the investigations carried out since the beginning of the international cooperation, and shows, by means of some examples, what insights can be derived from the tests.

• Journal of Gifted/Talented Education
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• v.10 no.2
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• pp.25-46
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• 2000

These purposes are to have a necessity to be educated for the linguistic gifted among many gifted in speedy changeable age, and to find out what differences are of properties between the linguistic gifted children and nongifted children through comparing/analysing to gifted children any nongifted children using performance evaluation on writer's ability. Therefore, it intends to use as a assisting material in order to develop ability and properties of the linguistic gifted children and nongifted children as well. The studying details are 1) to compare/analyze thinking ability between the linguistic gifted children and nongifted children 2) to find out differences of thinking ability for unrealistic reasoning between the linguistic gifted children and nongifted children. The studying subjects had been chosen 3 children as a first grade in 'C' Gifted Academy and 3 children as a first grade in an elementary school from June 3, 1999 to June 12, 1999. The studying instrument was an evaluation of linguistic properties certification(Project Spectrum : Krechevsky,'1994). It had got a frequency calculation, average and standard deviation through the material anylzing with the program SPSSWIN. The conclusions are as belows, First, as a result of performance evaluation on writer's ability to gifted children and nongifted children, the gifted children were outstandingly shown the linguistic ability getting much higher score than nongifted children in respect of vocabulary level, structure of writing, and consistency/logicality of theme. Second, it was shown the gifted children had diffusing thought than nongifted children through the esthetic question and impformation memories with listening to the realistic juvenil story and the unrealistic juvenile story.