• Survey Research
• /
• v.12 no.3
• /
• pp.173-186
• /
• 2011

We introduced the methodologies used to construct the longitudinal weights and cross-sectional weight that are required for the analysis of Korea Youth Panel Survey. To analyze the longitudinal dynamic change of the population, we derived the longitudinal weight through nonresponse adjustment based on logistic regression and post-stratification. Cross-sectional weights that are necessary to produce an asymptotically unbiased estimator of the population parameter were constructed through simple nonresponse adjustment based on overall response rate and post-stratification.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.64.2-64.2
• /
• 2017

The Population III (Pop III) stars are thought to be massive. If massive Pop III stars form binary system and they experience mass transfer via the Roche lobe overflow, this may significantly change the properties of the system. For example, mass transfer in such system may shorten the period of the system, forming short period binary black hole (BBH) system, which is the most promising candidate for recently detected gravitational wave radiation sources. Also, there is an expectation that due to the stripped envelope of donor star by mass transfer, this system can play a significant role in the cosmic reionization by emitting more UV photons. However, this outcome highly depends on the initial properties of the system. We perform grid calculation on Pop III binary models with various initial primary masses (20 ~ 100 solar mass), initial separations, and initial mass ratios (q = 0.5 ~ 0.9). We find that 1) in most cases binary models show no increase in the number of ionizing photons and 2) formation of short period BBH system via mass transfer is highly unlikely.

• 한국해양학회지
• /
• v.12 no.1
• /
• pp.13-32
• /
• 1977

In order to determine the distributional ecology, and to investigate factors influencing these features, the diatom communities in plankton at depths of one, twenty-five, fifty, and seventy five meters in the area were studied and measured over a fifteen month of period. Measurements of environmental factors including temperature and salinity and algal nutrients such as phosphate, silicate, nitrate, and ammonia were also made at the same depths and locations. The results indicate that the size of diatom communities and the species population changes were heavily dependent upon to season and location parameters as well as nutrient concentrations and hydrographic factors. Major factors influencing population distributions varied with principal species responsible for dominant species and species sucession. Two distinct distributional patterns in total diatom crop were observed in the study area. Maximum standing crop observed during spring and/or summer were related to the concentration of nutrients available at the onset of the spring bloom on a large scale. On a small scale, however, the distributions of total diatom standing crops were significantly correlated with both season/location factors and with hydrographic parameters as well. Vertical stratification of diatoms was observed only in the presence of the thermocline in the water column. Within the study area there was some seasonal consistancy in the composition of the species groups. However, some species association in these environments may vary with the change of season.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.6
• /
• pp.43-52
• /
• 2012

For this paper, a study targeting 9 forest patches in Dangjin to suggest for the wild birds, was conducted. The correlation between the emergence of wild birds and the forest vegetation was analyzed, and the patterns of forest vegetation for the improvement of species diversity were suggested by classifying wild birds and foraging guild by the type of forest vegetation. As for the characteristics of the wild birds emerged, more species and bigger population appeared in the vegetation type of mixed stand forest where the natural deciduous broadleaf trees and evergreen needleleaf trees coexisted in the large scale vegetation area. Thus, it was known that the advent of summer migratory birds and resident birds were affected the most by forest patches and vegetation types. As for foraging guild, the larger the forest paches the more the species and the population of the wild birds inhabiting in shrubs and bushes.

• The Korean Journal of Applied Statistics
• /
• v.21 no.4
• /
• pp.675-694
• /
• 2008

We propose a new sampling design for the Korean Livestock Production Cost Survey. In this sampling design, the survey population is derived from the 2005’s agricultural census of Korea. And coefficient of variation(CV) is estimated from the current livestock production cost survey data, and the estimated CV’s are used to find the optimal sample size which satisfies the predetermined precision of estimation. In order to save the enumeration cost, the agriculture enumeration districts are used as a primary sampling unit(psu). Final sample is selected by double sampling. Also, we propose the estimator which is able to reflect the change of the population of livestock production households.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.14
• /
• pp.5859-5861
• /
• 2015

Background: Kidney cancer has shown an increasing trend in recent decades. This study aimed to determine change in the incidence rate between 2003 and 2009 in Iran. Materials and Methods: In this study, national cancer registry data were used. Crude incidence rates were calculated per 100,000 and age-standardized incidence rates (ASRs) were computed using the direct standardization method and the world standard population. Significant trend of incidence rates was examined by the Cochran-Armitage test for linear trend. Results: A total of 6,944 cases of kidney cancer were reported. The incidence cases increased from 595 patients in 2003 to 1,387 patients in 2009. Sex ratio (male to female) was 1.67. ASR also increased from 1.18 in 2003 to 2.52 in 2009 per 100,000, but the increasing trend was not significant. Conclusions: A slow increasing trend of incidence rate was observed in the study population. This may be due to an increase of risk factors. It is suggested to perform a study on risk factors for the cancer.

• BMB Reports
• /
• v.44 no.1
• /
• pp.1-10
• /
• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.8 no.2
• /
• pp.67-79
• /
• 2012

As credit cards are more convenient than cash of heavy and volume, they are used widely in on_line (internet) and off_line in nowadays. A head of the economically active population had 4.8 credit cards in the third quarter 2011. The economically active population in their 20's and 30's may have more than 10 credit cards. If the membership card and point card are included, the count rise to 20 cards in a man. Therefore, the their purse become thick by several cards. Nowadays, the smart-phone is widely used. Therefore, a lot of credit cards are come in smarty-phone from analog form to digital form. In this paper, we study a method of digital credit cards management in smart-phone. For the method, the hardware need in small and existing system have a few change. All kinds of credit cards are used in smarty-phone. We compare the method with Moneta card and NFC of smarty-phone. The digital credit cards feature a light, safety and convenience of mobile users in several ways.

• Journal for History of Mathematics
• /
• v.25 no.1
• /
• pp.45-56
• /
• 2012

Mathematical biology has been recognized its importance recently and widely studied in the fields of mathematics, biology, medical sciences, and immunology. Mathematical ecology is an academic field that studies how populations of biological species change as times flows at specific locations in their habitats. It was the earliest form of the research field of mathematical biology and has been providing its basis. This article deals with various form of interactions between two biological species in a common habitat. Mathematical models of predator-prey type, competitive type, and simbiotic type are investigated.

• Korean Journal of Microbiology
• /
• v.8 no.2
• /
• pp.69-76
• /
• 1970

1. The yeasts in the two samples of Nuruk (mold wheat) which one prepared at the College of Agriculture, Choong-Nam University (S) and the other purchased at a market(T), were examined and counted. The yeasts were differe entiated by the market (T), were examined and counted. The yeasts were differe entiated by the TTC(2,3,5-triphenyltetrazolium chloride)agar overlay technique that yields a varied shade of color. The results were : the population of yeasts in 1g of Nuruk S was about $6{\times}10^4$, 56.5% of which were TTC-pink yeasts, 16% TTC-red pink yeasts, 8% were TTC-red yeasts, and 16.5% TTC-white yeasts. In Nuruk T(1g), the number of yeasts accounted for $14{\times}10^4$ and constituted of 42% TTC0pink, 21% TTC-red pink, 23% TTC-red and 9% TTC-white. 2. During the fermentation of Takju (Korean Sake) employing the Nuruk S and T the yeast flora throughout the brewing were observed in 12 hour intervals. TTC pink and red yeasts considered to be the major yeasts were isolated all cultured. The strains ($1{\times}10^5$/ml) were added to the mashes S and T in which pH was adjusted to 4.2 and the change of yeast flora was examined during fermentation.