• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1175-1187
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• 2007

This paper proposes a novel crest factor reduction (CFR) algorithm to be deployed on WCDMA basestation. Generally speaking, it is well described that the reduction of peak-to-average ratio (PAR) yields the possibility of using low cost power amplifier such that the basesation becomes economic However, the simple reduction of PAR could degrade the signal quality measured by either peak code domain error (PCDE) or error vector measurement (EVM), and the level of channel interference constrained by adjacent channel leakage ratio (ACLR). Regarding these imperfections, this paper introduces an effective CFR algorithm in which the function of filter-dependent CFR (FDCFR) incorporated with the histogram-based waterfilling code domain compensation (HBWCDC) carries out. To verify the performance of the proposed CFR technique, substantial simulations including comparative works are conducted with obeying W-CDMA basestation verification specification. To exploit the superiority, the performance of the proposed method is tentatively compared with that associated to the simple memoryless clipping method and the memory-required filter-dependent clipping method.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.218-223
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• 2010

The zinc oxide thin film, which can be applied as the gas sensor of a semiconductor type, was grown on the silicon substrate by CFR(continuous flow reaction) method in this study. The growth property and the electrical property of the zinc oxide thin films synthesized by CFR method were also investigated. Zinc acetate solutions of 0.005~0.02 M were used as the precursor for the preparation of zinc oxide thin films. The size of ZnO particles consisted on the zinc oxide thin film increased not only with increasing concentration of precursor, but also the thickness of thin film increased. The growth rate of zinc oxide thin film by CFR method was proportionably depend on the concentration of precursor and the uniform ZnO thin film was prepared when zinc acetate of 0.01 M is used as the precursor. The charged currents on the zinc oxide thin films were obtained as its electrical property by I-V meter, and increased agree with increasing the thickness of zinc oxide thin film. Thus, it was concluded that the charged current on the zinc oxide thin film can be controlled with changing concentration of precursor solution in CFR method. The charged currents on the zinc oxide thin films also decreased when ZnO thin film is exposed under hydrogen sulfide of 500 ppmv at $300^{\circ}C$ for 5 min. From these results, it could be confirmed that the zinc oxide thin film prepared by CFR method can be used for the detection of sulfur compounds.

• Korean Journal of Logic
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• v.17 no.2
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• pp.323-349
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• 2014

In this paper, we show that the standard completeness for the extension of UL with compensation-free reinforcement (cfr) $(({\phi}&{\psi}){\rightarrow}({\phi}{\wedge}{\psi})){\vee}(({\phi}{\vee}{\psi}){\rightarrow}({\phi}&{\psi}))$ can be established. More exactly, first, the compensation-freely reinforced uninorm logic $UL_{cfr}$ (the UL with (cfr)) is introduced. The algebraic structures of $UL_{cfr}$ are then defined, and its algebraic completeness is established. Next, standard completeness (i.e. completeness on [0, 1]) is established for $UL_{cfr}$ by using the method introduced in Yang (2009).

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1-5
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• 2010

The Hyundai Rotem company is due to be conducted the main line Speed Qualification Test as regulated by CFR for SEPTA EMU and SCRRA Bi-level coach project. The regulated test items per 49CFR213.345 are wheel/rail interaction forces and carbody/truck accelerations during running on main line. Therefore the special two sets of instrumented wheelset (IWS) per each project have been made for measuring the interaction forces between wheel and rail at four wheels of one truck during running on main line. In this paper, regarding Speed Qualification Test, the required test items and data analysis method per 49CFR213.345 and the preparation status of instrumented wheelsets (IWS) are introduced.

• Journal of Korea Multimedia Society
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• v.5 no.2
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• pp.158-166
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• 2002

In this paper, we proposed a contour shape description method which use the CFR(contour fluctuation ratio) feature. The CFR is the ratio of the line length to the curve length of a contour segment. The line length means the distance of two end points on a contour segment, and the curve length means the sum of distance of all adjacent two points on a contour segment. We should acquire rotation and scale invariant contour segments because each CFR is computed from contour segments. By using the interleaved contour segment of which length is proportion to the entire contour length and which is generated from all the points on contour, we could acquire rotation and scale invariant contour segments. The CFR can describes the local or global feature of contour shape according to the unit length of contour segment. Therefore we describe the shape of objects with the feature vector which represents the distribution of CFRs, and calculate the similarity by comparing the feature vector of corresponding unit length segments. We implemented the proposed method and experimented with rotated and scaled 165 fish images of fifteen types. The experimental result shows that the proposed method is not only invariant to rotation and scale but also superior to NCCH and TRP method in the clustering power.

• Journal of Radiation Protection and Research
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• v.43 no.3
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• pp.124-129
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• 2018

Background: Effluent Concentration Limits (ECLs) were re-evaluated via direct calculation using dose coefficients based on radiation protection quantity introduced in Korea and the intrinsic breathing rates of Korean residents. Materials and Methods: The re-evaluated ECLs were compared with the domestic standards given in the Notice of the Nuclear Safety and Security Commission (NSSC), as well as with ECLs specified in the Code of Federal Regulations (CFR). Results and Discussion: The relative ratios of the re-evaluated ECLs to the currently applied domestic standards differed depending on the radionuclide type, but it was clearly shown that, for tritium ($^3H$) and radiocarbon ($^{14}C$), which significantly affect radiological dose to the public during the normal operation of nuclear power plants, the re-evaluated ECLs were higher than the domestic standards. This implies that Korean standards are relatively conservative. Conclusion: The re-evaluated results for each age group showed that $^{131}I$ (radioiodine), one of the significant radionuclides, had the lowest values, but nonetheless, the domestic standards for radioiodine were lower than the ECLs given in the CFR and the re-evaluated ECLs via a method given in the CFR.

• Fire Science and Engineering
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• v.30 no.4
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• pp.20-26
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• 2016

When the fire takes place in Nuclear Powr Plants(NPPs), the reactor should achieve and maintain safe shut-down conditions and minimize the radioactive material released to the environment. The U.S. Nuclear Regulatory Commission (NRC) has issued numerous generic communications related to fire protection over the past 20 years, after it issued its requirements in the Fire Protection Rule set forth in Title 10, Section 50.48 of the Code of Federal Regulations (10 CFR 50.48) and Appendix R to the 10 CFR 50. The and Nuclear Energy Institute (NEI) has developed a Methodology for Risk Informed Fire Safe-Shutdown Analysis, which is related to the Deterministic Method for Multiple Spurious Operations solutions. The aim of this study was to identify, achieve, and maintain Post-Fire Safe-Shutdown of the Main Control Room (MCR) of the CANDU reactor, even though one train of the multiple Safety Structures, Systems, and Components (SCCs) fail by the technical specification and analysis method.

• Carbon letters
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• v.4 no.2
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• pp.57-63
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• 2003

In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and $Et_3N$ and $NH_4OH$ as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using $Et_3N$ as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 $m^2/g$, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with $CO_2$ leads to the formation of activated carbon with a wide range of surface area (503~1119 $m^2/g$) with both of these resins. The maximum pore volume percentage was obtained in 3-20 ${\AA}$ region by physical activation method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.205-213
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• 2011

The Long Term Evolution (LTE) system is designed to provide a high quality data service for fast moving mobile users. It is based on the Orthogonal Frequency Division Multiplexing (OFDM) and relies its channel estimation on the training samples which are systematically built within the transmitting data. Either a preamble or a lattice type is used for the distribution of training samples and the latter suits better for the multipath fading channel environment whose channel frequency response (CFR) fluctuates rapidly with time. In the lattice-type structure, the estimation of the CFR makes use of the least squares estimate (LSE) for each pilot samples, followed by an interpolation both in time-and in frequency-domain to fill up the channel estimates for subcarriers corresponding to data samples. All interpolation schemes should rely on the pilot estimates only, and thus, their performances are bounded by the quality of pilot estimates. However, the additive noise give rise to high fluctuation on the pilot estimates, especially in a communication environment with low signal-to-noise ratio. These high fluctuations could be monitored in the alternating high values of the first forward differences (FFD) between pilot estimates. In this paper, we analyzed statistically those FFD values and propose a postprocessing algorithm to suppress high fluctuations in the noisy pilot estimates. The proposed method is based on a localized adaptive moving-average filtering. The performance of the proposed technique is verified on a multipath environment suggested on a 3GPP LTE specification. It is shown that the mean-squared error (MSE) between the actual CFR and pilot estimates could be reduced up to 68% from the noisy pilot estimates.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.12-19
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• 2014

To minimize the risk of corrosion on buried pipeline and to maximize the efficiency of cathodic protection, various indirect inspection techniques have been used for decades. In the United States, 49 CFR has regulated the external corrosion direct assessment for buried pipelines. In Korea, there is no provision for external corrosion direct assessment but there is only, according to the KGS Code, provision that if the survey of the defects of buried pipeline and the leakage test for the pipe were conducted, it is deemed to leakage inspection. We, therefore, have suggested external corrosion direct assessment method appropriate to domestic status through the survey of the regulations and standards of UK and the USA and the investigation of domestic situation on coating damage detection method. The proposed external corrosion direct evaluation method was used as the basis when introducing the precision safety diagnosis regulation for the medium-pressure pipe in Korea.