• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.499-504
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• 2012

The specific rates of sovolysis of 4-methylthiophene-2-carbonyl chloride (1) have been determined in 26 pure and binary solvents at $25.0^{\circ}C$. Product selectivities are reported for solvolyses of 1 in aqueous ethanol and methanol binary mixtures. Comparison of the specific rates of solvolyses of 1 with those for p-methoxybenzoyl chloride (2) in terms of linear free energy relationships (LFER) are helpful in mechanistic considerations, as is also treatment in terms of the extended Grunwald-Winstein equation. It is proposed that the solvolyses of 1 in binary aqueous solvent mixtures proceed through an SN1 and/or ionization (I) pathway rather than through an associative $S_N2$ and/or addition-elimination (A-E) pathway.

• Journal of Communications and Networks
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• 제12권1호
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• pp.30-42
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• 2010

In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

• 토지주택연구
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• 제8권4호
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• pp.257-266
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• 2017

LH has been using ultra high strength reinforcing bars (SD500 and SD600), since 2011. Such a change requires an adjustment of the old extra rates of bar splice to reflect use of ultra high strength reinforcing bars, as these rates had been set based on SD400 bars. It is particularly difficult to calculate precisely rebar lap-splice locations for large areas, such as those in apartment buildings. This research aims to adjust the extra rates of bar splice to reflect a reasonable rate; the rebar lap-splice length is not an exact estimation, but instead, an extra rates of bar splice is set and the rebar lap-splice length is increased by 2% (D 10) - 7% (025) depending on the bar size. The subjects of this study are LH apartments undergoing frame construction. We studied the quantity estimations from the design drawings, and analyzed the settlement quantities of construction field. The results of the study revealed that, when each of the quantities are analyzed, consider adjusting the extra rates of bar splice of some rebar to 1% - 3.5%. This was caused by an overuse of reinforcing bars in onsite construction and the use of supporting bars that have not been reflected in the documents, among other reasons. Based on the results of our study, an improvement plan for the current extra rates of bar splice seems to be necessary, cutting or raising the rate depending on the analysis of the data. Through this study, we expect to contribute to the calculation of reasonable construction costs, improvements in the quality of rebar work, and improvements in the capacity of design techniques for apartment buildings.

• Journal of the Korean Data and Information Science Society
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• 제18권2호
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• pp.553-560
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• 2007

In this paper, we consider two components system which lifetimes have Freund's bivariate exponential model with equal failure rates. We propose Bayesian multiple comparisons procedure for the failure rates of I Freund's bivariate exponential populations based on Dirichlet process priors(DPP). The family of DPP is applied in the form of baseline prior and likelihood combination to provide the comparisons. Computation of the posterior probabilities of all possible hypotheses are carried out through Markov Chain Monte Carlo(MCMC) method, namely, Gibbs sampling, due to the intractability of analytic evaluation. The whole process of multiple comparisons problem for the failure rates of bivariate exponential populations is illustrated through a numerical example.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.807-812
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• 2001

This paper represents the wall thinning analysis results for secondary side piping of two types of domestic nuclear power plants based on the DB establishment and F AC analysis study for NPP secondary system piping. CHECWORKS code utilized in this study has been applied world widely to wall thinning analyses for secondary side piping and its reliability has also been proved. The predicted wear rates for several piping systems of a pressurized water reactor NPP are compared with those of a pressurized heavy water reactor NPP and with the measured wear rates. On the basis of comparison results of the predicted and measured wear rates, the analysis results can be effectively applied to the development of a standard thinned pipe management program targeted all domestic nuclear power plants.

• 해양환경안전학회지
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• 제8권2호
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• pp.61-69
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• 2002

The relatively rapid rising trend of crime rates in marine situations leads to social concerns in Korea. This study reviews some theoretical backgrounds of the economics of crime and applies econometric models to Korean marine crimes. This research finds that there is a negative relationship between marine crime rates and unemployment rates and a positive relationship between the price level and marine crimes in Korea. The other finding results are that unemployment elasticities are higher in the 1980s and price elasticities are higher in th 1990s in comparison with the results of the other periods. This findings are incompatible with the previous theoretical researches in advanced countries. These findings show that In rapidly growing economy, marine crime occurrence is proportional to marine economic activity frequency. This result may reflect that marine crimes are different from land crimes.

• Asian Journal of Atmospheric Environment
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• 제5권1호
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• pp.1-7
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• 2011

This study assesses the dispersion and emission rates of odor form industrial area source. CALPUFF and AERMOD Gaussian models were used for predicting downwind odor concentration and calculating odor emission rates. The studied region was Seobu industrial complex in Korea. Odor samples were collected five days over a year period in 2006. In-site meteorological data (wind direction and wind speed) were used to predict concentration. The BOOT statistical examination software was used to analyze the data. Comparison between the predicted and field sampled downwind concentration using BOOT analysis indicates that the CALPUFF model prediction is a little better than AERMOD prediction for average downwind odor concentrations. Predicted concentrations of AERMOD model have a little larger scatter than that of CALPUFF model. The results also show odor emission rates of Seobu industrial complex area were an order of 10 smaller than that of beef cattle feed lots.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2002년도 추계학술발표회
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• pp.149-160
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• 2002

The relatively rapid rising trends of crime rates in marine situations leads to social concerns in Korea. This study reviews some theoretical backgrounds of the economics of crime and apply econometric models to Korean marine crimes. We find that there is a negative relationship between marine crime rates and unemployment rates and positive relationship between price level and marine crime in Korea. And also we find that unemployment elasticities are higher in the 1980s' and price elasticities are higher in th 90's in comparison with the results of the other periods. This findings are incompatible with the previous theoretical researches in advanced countries. This findings show that in rapidly growing economy, marine crime occurrence is proportional to marine economic activity frequency. This result may reflect that marine crimes are different from land crimes.

• 전자공학회논문지B
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• 제32B권12호
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• pp.1614-1623
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• 1995

In this paper we propose a region-adaptive CELP image coder for still images at low bit rates below 0.5 bpp. The proposed method partitions the image into stochastically similar regions by the minimum spanning tree method and finds prediction coefficients for each region using a 2- dimensional linear prediction model. Coding is carried out on 8$\times$8 blocks and when there are several regions included in a block, an image is synthesized using the prediction coefficients of each region. Computer simulation results show that the proposed method allows improved synthesized image over conventional block-adaptive CELP methods, especially at edges. In addition, performance comparison with the JPEG DCT method shows that while the JPEG method shows block distortion and staircase effects (ragged edges) at bit rates below 0.5 bpp, the proposed CELP method shows improved synthesized images with such effects reduced.

• 지역사회간호학회지
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• 제12권1호
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• pp.168-174
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• 2001

This study was conducted to investigate the disease preventive behavior and health promoting behavior of a community residents. The subjects were selected by convenient sampling and the total number was 300(Female, 170, Male, 130). The data were collected by face to face interviews during the period of Sep. 15-30, 1999. The measurement tool for this study was the rating score for disease preventive behavior and health promoting behavior. The instrument was developed by the researcher based on the tool of Korea Institute for Health and Social Affairs. The data were analyzed by percentage, mean, t-test, ANOVA. $x^2-test$ by Windows SPSS/PC program(v7.5). The results were as follows: 1. In the comparison of disease preventive behavior rates between male and female, there was a statistically significant difference in physical examination, measuring the blood pressure and vaccination for B type hepatitis. In the comparison of disease preventive behavior rates among the age, there was a statistically significant difference in physical examination, measuring the blood pressure. 2. The rating score for the health promoting behavior of the men subjects was lower than that of the women subjects. In the comparison of health promoting behavior scores between male and female, there was a statistically significant difference in smoking, drinking, regular exercise, breakfast eating, vegetable consumption and teeth brushing. In the comparison of promoting Behavior scores among the age, there were significant difference, there was a statistically significant difference in smoking, sleeping, seat belt use, breakfast eating and salty eating.