• Journal of the Korea Institute of Building Construction
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• 제12권1호
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• pp.108-114
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• 2012

Escalation method examining the changes in price index has been widely utilized in public construction projects. The previous escalation method determined estimated changes in price based on the average unit price of contract items over a period of time. In relation to this method, the issue has been raised that the fluctuation rates of previous method show different trends compared with other related price indices, as the influence of the small group of contract items with large unit prices overwhelms the others. This research suggested an improved escalation method which estimates the fluctuation rate by examining the changes in CCI (construction cost index) and applies it to the total amount or the partial amount deducted for labor cost in price escalation for previous bid price method. To verify the improvement, a case study is conducted on an educational facility, and the fluctuation rate was estimated in two different base periods (short term, long term). The results over the long term showed similar tendencies to those of related price indices, as well as significant differences in fluctuation rates compared to those of the previous method.

• Journal of the Korean Society of Combustion
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• 제13권2호
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• pp.14-22
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• 2008

The CH* chemiluminescence of premixed flames and their dependency on fuel types has been experimentally investigated on laminar methane and propane premixed flames. The measured chemiluminescence intensities are observed linearly proportional to the fuel flow rate, which could be interpreted as the CH* chemiluminescence signal is linearly proportional to the heat release rate under fuel lean conditions. The effect of equivalence ratio could be expressed by an exponential function as ${I_{CH*}}^{\propto}\;a_1\;{\exp}(b_1{\Phi})$, where $a_1\;=\;0.00054$ and $b_1\;=\;4.60$ for methane and $a_1\;=\;0.0056$ and $b_1\;=\;5.02$ for propane. Oscillating flames showed the temporal fluctuation of chemiluminescence intensity: however, the time averaged values are virtually identical to those of quiescent flames under the same fuel flow rate and equivalence ratio conditions. This observation suggests that there is no significant flame stretch effect on chemiluminescence intensity, in average values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제10권4호
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• pp.483-494
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• 1998

This study describes the characteristics on impeller discharge flow of a centrifugal compressor with vaneless diffuser. Distorted flow at impeller exit was investigated by measuring of unsteady velocity fluctuation using hot-wire anemometer. As a result, a wake region appears near shroud side and moves to suction side and also to hub side as flow rate decreases. Jet, wake, and their boundary region which can be defined in jet-wake flow model are clearly observed at a high flow rate for the flow coefficient of 0.64, however, as flow rate decreases to the flow coefficient of 0.19, the classification of their regions disappears. Turbulence intensity also increases as flow rate decreases. Measurement error from uncertainty analysis is estimated about 4% at the flow coefficient of 0.19

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.1051-1054
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• 2008

The entropy production in a non-equilibrium state based on the reversible Oregonator model of the Belousov-Zhabotinskii (BZ) reaction system has been studied. The reaction affinity and the reaction rate for the individual steps have been calculated by varying the concentrations of key variables in the system. The result shows a linear relationship between the reaction affinity and the reaction rate in the given concentration range. However, the overall entropy calculated on the basic assumption that the entropy in a reaction system corresponds to the summation of a product of reaction affinity and reaction rate of individual steps shows a nonlinearity of the reaction system. The results well agrees with the fact that the entropy production is not linear or complicated function in a non-linear reaction system.

• Korean Journal of Childcare and Education
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• 제9권6호
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• pp.197-221
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• 2013

The purpose of this study was to examine the relationship between the child care support policies and the birth rate in 33 OECD countries. In the structural equation modelling, the birth rate was the dependent variable while the cash-support policies, the child-care facility service policies, and the tax benefits policies were the independent variables. The analysis showed that the most effective factor on the birth rate was the child-care facility service policies. Regarding the effectiveness of the policy expenses, the cash-support policies showed stable fluctuation of effectiveness according to the fluctuation of cash amount, the child-care facility service policies. In conclusion, in order to increase the effectiveness of the cash-support policies, the adequate cost calculation to decrease the parents' burden for child-bearing, re-allocation of budget, and support methods and timing should be continually discussed. In addition, for the better effectiveness of the facility service policies, more various, comprehensive and high-quality facility service policies that could balance home and work, should be implemented.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제39권2호
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• pp.187-192
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• 1994

This study was conducted to investigate varietal difference in viviparous germinability at different days after heading and temperature conditions. Three Japonica rice varieties, Sobaekbyeo, Odaebyeo and Hwaseongbyeo, and Sare type rice variety, Jakwangdo, showed higher viviparous germination rate from 20 days after heading, while a Tongil type rice, ]ungwonbyeo, and a Indica varieyt, IR-20, showed still low viviparous germination at 40 days after heading. Viviparous germination rate of rice varieties observed at 4 and 10 days after incubation was greately increased with increasing temperature from 15$^{\circ}C$ to 3$0^{\circ}C$ , and germination rate less than 5% was observed at 4 days after incubating at 15$^{\circ}C$ in all rice varieties teased. Viviparous germination pattern of rice varieties was divided into two types. Three Japonica and Sare type rice varieties showed higher and faster in viviparous germination than a Tongil type and Indica rice verieties. Viviparous germination was delayed under day /night fluctuation of incubation temperature compared with day /night fluctuation of incubation temperature compared with day /night constant condition at the same average temperature. The optimum incubation temperature and duration to evaluate viviparous germinability of rice varieties were 25/15$^{\circ}C$ and 6 days, respectively.

• Journal of Korean Library and Information Science Society
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• 제38권2호
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• pp.31-50
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• 2007

This paper presents a scientometric analysis of the growth of literature output in the field of Hepatitis covered in three bibliographic databases namely MEDLINE, CINAHL and IPA. The literature covered in three databases for the period 1984-2003 was considered. MEDLINE covered the maximum of 75750 records during the study period 1984 to 2003. This is followed by CINAHL and IPA databases. It is found that the annual growth rate of literature in a particular field of knowledge will not be uniform and in order to measure the rate of growth from year after year, the application of RGR is quite appropriate. The RGR has shown a decreasing trend, with a slight fluctuation of growth rate for the years 1985 and 1997. The output by colleges, universities, corporate sector and research institutions with reference to RGR and Dt has shown mixed results such as increasing trend, decreasing trend and fluctuation trend. Hepatitis research indicates a different picture when the RGR and Dt were calculated by year-wise both in terms of number of papers and number of pages.

• IEIE Transactions on Smart Processing and Computing
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• 제1권3호
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• pp.152-160
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• 2012

This paper proposes a frame-level rate control algorithm for low delay video applications to reduce the fluctuations in the bitrate. The proposed algorithm minimizes the bitrate fluctuations in two ways with minimal coding loss. First, the proposed rate control applies R-Q model to all frames including the first frame of every group of pictures (GOP) except for the first one of a sequence. Conventional rate control algorithms do not use any R-Q models for the first frame of each GOP and do not estimate the generated-bit. An unexpected output rate result from the first frame affects the remainder of the pictures in the rate control. Second, a rate-distortion (R-D) cost is calculated regardless of the hierarchical coding structure for low bitrate fluctuations because the hierarchical coding structure controls the output bitrate in rate distortion optimization (RDO) process. The experimental results show that the average variance of per-frame bits with the proposed algorithm can reduce by approximately 33.8% with a delta peak signal-to-noise ratio (PSNR) degradation of 1.4dB for a "low-delay B" coding structure and by approximately 35.7% with a delta-PSNR degradation of 1.3dB for a "low-delay P" coding structure, compared to HM 8.0 rate control.

• Journal of the Korean Data and Information Science Society
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• 제20권4호
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• pp.655-660
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• 2009

As the global economic crisis, the Korean foreign exchange market appears unstable with large fluctuations in exchange rate. Inevitably, there is growing attention on price variables such as exchange rate and interest rates and also on corelation between the factors. This is an empirical study on the causality of fluctuation between exchange rate and interest rate in the Korean market under global economic crisis. The fluctuations in won/dollar exchange rate and call rate are described and followed by analysis of lead-lag relationship between the two variables using Cross-correlation function and Granger causality test.

• Journal of Korean Society of Rural Planning
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• 제22권4호
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• pp.147-157
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• 2016

On the purpose to analyze the survival rate of startup companies since their establishment, the companies' survival rate was investigated by surviving period. The average and coefficient of variation(C.V.) of the startup companies' survival rate were examined with the comparison of urban and rural areas, and primary, secondary, and tertiary industries. In this study, the variation of total numbers of new-established companies, from 1998 to 2012, were analyzed with micro-data of the Statistics Korea, 'The Census on Establishments'. The results show that the survival rate of primary industry companies largely fluctuate and don't be stabled during the whole surviving periods, whereas secondary and tertiary industry companies show stabilized survival rate after fifth year from their establishment. Especially, the startup companies of primary industry located at urban areas show the largest fluctuation and the most vulnerable stability of survival rate. It is concluded that the surviving period of primary industry companies don't guarantee their survival, while survival rate of secondary and tertiary industry company became stable after five years from their establishment.