• Journal of Korean Institute of Industrial Engineers
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• v.41 no.5
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• pp.488-498
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• 2015

Research on stem cells can be divided into three categories : pluripotent stem cell, adult stem cell, and induced pluripotent stem cell. Technology life cycle (TLC) on research stage is analyzed for the three stem cell categories based on diffusion model. Three diffusion models-logistic, Bass, and Bass model with integration constant (BMIC)-are applied to the number of articles related to each stem cell category in SCOPUS lists. Two different parameter estimation methods is used for each of logistic and Bass model. Results show that (1) the current year, 2015, lies in growth period at pluripotent stem cell and adult stem cell, and lies in growth period or maturity period at induced pluripotent stem cell. (2) Model fitness is the highest at BMIC model. (3) Imitation effect works best at the research area of induced pluripotent stem cell.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.648-657
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• 2021

This study was conducted to estimate the volume growth by forest type and major species using the national forest resource inventory and to predict the final age of maturity by deriving the mean annual increment (MAI) and the current annual increment (CAI). We estimated the volume growth using the Chapman-Richards model. In the volume estimation equations by forest type, coniferous forests exhibited the highest growth. According to the estimation formula for each major species, Larix kaempferi will grow the highest among coniferous tree species and Quercus mongolica among broad-leaved tree species. And these estimation formulas showed that the fitness index was generally low, such as 0.32 for L. kaempferi and 0.21 for Quercus variabilis. In the analysis of residual amount, which indicates the applicability of the volume estimation formula, the estimates of the estimation formula tended to be underestimated in about 30 years or more, but most of the residuals were evenly distributed around zero. Therefore, these estimation formulas have no difficulty estimating the volume of actual forest species in Korea. The maximum age attained by calculating MAI was 34 years for P. densiflora, 35 years for L. kaempferi, and 31 years for P. rigida among coniferous tree species. In broad-leaved tree species, we discovered that the maximum age was 32 years for Q. variabilis, 30 years for Q. acutissima, and 29 years for Q. mongolica. We calculated MAI and CAI to detect the point at which these two curves intersected. This point was defined by the maximum volume harvesting age. These results revealed no significant difference between the current standard cutting age in public and private forests recommended by the Korea Forest Service, supporting the reliability of forestry policy data.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.335-342
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• 2012

This study was conducted to estimation the selection response for growth-related traits in 31-month old of Pacific abalone, Haliotis discus hannai were born in 2008. In overall mean of surveyed traits and standard deviation showed $76.31{\pm}7.247$ mm of shell length, $49.48{\pm}5.307$ mm of shell width and $40.96{\pm}6.80$ g of total weight. The effect of sex and maturity were statistically significant in all traits include out a condition factor (p < 0.01). And In effect of sex, female were higher than male in all traits excepting condition factor, significantly. In correlation between breeding value and phenotypic value by each traits, showed rank correlation coefficient and simple correlation coefficient, which represented low positive correlation. A hopeful genetic improvement to the next generation showed 6.96 mm of shell length, 4.47 mm of shel width and 12.93 g of total weight. Therefor, It is considered that if considering properly selection intensity and selection ratio, efficient improvement could be made.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.327-334
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• 2004

In this paper, method for the determination of removal time of the side forms in high strength concrete are discussed using the estimation model of compressive strength development, the development of bond strength and rebound number of P type Schmidt hammer in order to review the validity of existing regulation as to side form removal and offer effective quality control method. According to the results, as W/B increases by $10\%$, the setting time is shortened by about 2 hours. In the scope of the paper, required time to gain 8MPa of compressive strength is determined about 17 ${\~}$20 hours of age and $21{\~}25^{\circ}D{\cdot}D$ of maturity. Bond strength between form and concrete shows the highest value around final setting time, but decreases drastically after that. Amount of concrete sticking on the form is large before setting completed, but after that, its amount shows decline tendency. The rebound value test with P type schmidt hammer can be started faster by 2${\~}$3 hours than compressive strength test. It is also confirmed that the removal of forms is possible when the rebound value of P type schmidt hammer is more than 32. It is found from the results that existing regulation regarding removal time of the side form of high strength concrete provided in KCI needs no revision because required time to gain the strength provided in KCI has no adverse effect on strength development at early age and surface condition during stripping the side form. Effective procedure to decide the removal time of side form can be performed by applying P type Schmidt hammer.

• Journal of Animal Science and Technology
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• v.54 no.6
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• pp.395-400
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• 2012

This study was conducted to estimate the growth curve parameters for the body weight (BW) and body length (BL) of miniature pigs in Korea. Growth curve parameters were estimated through a nonlinear regression model using Gompertz, Logistic, and von Bertalanffy methods. A total of 25 piglets were measured monthly from birth up to 15 months of age to estimate both body weight and length. Results showed that the estimated average values for the body weight (body length) were 31.83 kg (58.77 cm) for the mature weight (A), 3.06 (1.74) for the growth ratio (${\beta}$), and 0.28 (0.52) for the maturing rate (${\kappa}$). Average inflection points showing maximum growth rate estimated each month for body weight were 3.97 kg and 11.70 cm, while for the body length were 1.06 kg and 21.61 cm. Moreover, the estimated maturation rates of the body weight and length for the group of Sire 1 were 0.22 and 0.40 respectively, whereas for the group of Sire 2 these values were 0.34 and 0.39. On the other hand, for the groups of Dam 1, Dam 2, and Dam 3, maturation rates for their body weights were 0.26, 0.28 and 0.33 respectively, while for their body lengths these values were 0.43, 0.37, and 0.38, respectively. The study also indicated a negative relationship between the values of mature weight and maturity rate for the body weight will result to a higher inflection point which is in contrast for the body length where results show that a positive relationship between the values of mature length and the maturity rate will result to a higher inflection point. Furthermore, the growth performance of miniature pig varies across stages but using these estimated growth curve parameters could improve the genetic traits of miniature pig.

• Korean Journal of Poultry Science
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• v.16 no.4
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• pp.239-252
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• 1989

The present study was carried out to investigate the improvement of major production traits with the published data of twenty-two years'random sample tests held in Korea from 1966 to 1988. Eight traits-roaring viability, laying viability, age of sexual maturity, hen day egg production, hen-housed egg production, egg weight, feed requirement, 500 days body weight-were dealt with in this study. The results obtained in this study are summerized as follows； 1. Total mean value for rearing viability was 99.4% in 1980s. Mean value for rearing viability of colored hen was 99.5% and white hen was 99.06% in 1980s. Mean value for laying viability was increased by 0.98%, 0.86% and 0.86% per year in pool data, white hen and colored hen, respectively. 2, Age of sexual maturity was decreased from 171.1 day to 160.8 day in pool data during 1960s- 1910s but increased to 162.4 day in 1980s； and decreased from 160.5 day to 1595 nay in white hen but increased from 163.7 day to 166.1 day in colored hen during 1970s-1980s. 3. Mean values for hen-day egg production were increased by 0.96%, 1.09% and 0.63% per year in pool data, colored hen and white hen, respectively. 4. Mean values for hen housed egg production were increased by 45, 5.37 and 4.23 per year in pool data, colored hen and white hen, respectively. 5. Egg weight were improved by 0.22g and 0.25g per year in pool data and colored hen but decreased by 0.03g in white hen. 6. feed requirement were improved by 0.04, 0.05 and 0.1 per year in pool data, white hen and colored hen, respectively. 7. 500 days body weights were increased by 0.38g per year in pool data but decreased by 14.95g and 10.37g in colored hen and white hen, respectively. 8. Estimate of correlation coefficient between age of sexual maturity and other factors such as hen day egg production. hen housed egg production, egg weight and 500 days body weight were -0.4512, -0.2876, -0.4376 and 0.2045 in pool data； -0.358, -0.1530 0.3475 and 0.1208 in white hen； 0.0989, 0.1181, 0.2885 and 0.2248 in colored hen, respectively. Estimates of correlation coefficient between hen day egg production and egg weight were 0.6233, -0.2259 and 0.2973 in Pool data, white hen and colored hen； between hen day egg production and 500 days body weight, 0.2417, 0.0774, -0.4787 ： between hen-housed egg production and egg weight, 0.6171, -0.2706, 0.4579： between hen housed egg production and 500 days body weight, 0.3082, -0.0792, -0.3368： between egg weight and 500 days body weight, 0.2742, 0.2205, 0.1354, respectively.

• Knowledge Management Research
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• v.14 no.1
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• pp.73-94
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• 2013

Customer's purchase state consists of purchase inertia and variety-seeking. As the growing brand familiarity triggers the increase of brand attractiveness, customers purchase state will be of inertia. However the excessively growing brand familiarity ignites the decrease of brand attractiveness. Followingly the purchase state will be tend to plunge into the variety-seeking state. The main topic of this study is to validate the asymmetric formation of customer's purchase states between inertia and variety-seeking. In order to follow up the main topic, this article introduces a model to freely describe the velocity of value changes depending upon the purchase states. This model will help overcome the limitation of the past studies having been based on the symmetric value changes. Based on this approach marketer will be able to decide the timing of sales promotions. This research utilized local telecommunication carrier's database of smartphone application purchase/download records. This database was collected from two years (2009 and 2010) span, the time when the smartphones started commodifying in Korea whilst most of the past studies had used purchase data of maturity stage products. From this approach utilizing the introduction stage data in the product life cycle, the probability of brand choice depending upon the purchase state on the early-stage can be probed. Moreover, this study tries to expand the research methodology from the other areas of research by knowledge sharing. Here this study introduces the methodology of section-aggregated multinomial logit to simultaneously estimate the parameters that were included in the plural multinomial logit functions while the plural functions were inter-connected. This adoption of section-aggregated multinomial logit model procedures from the computerized statistics areas is expected to nourish the marketing research for more precise analysis and estimation of effects of marketing activities.

• The Korean Journal of Applied Statistics
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• v.28 no.3
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• pp.393-406
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• 2015

We examine how to model mortality risk using the adaptation of the mean-reverting processes for the two factor model proposed by Cairns et al. (2006b). Mortality improvements have been recently observed in some countries such as United Kingdom; therefore, we assume long-run mortality converges towards a trend at some unknown time and the mean-reverting processes could therefore be an appropriate stochastic model. We estimate the parameters of the two-factor model incorporated with mean-reverting processes by a Metropolis-Hastings algorithm to fit United Kingdom mortality data from 1991 to 2015. We forecast the evolution of the mortality from 2014 to 2040 based on the estimation results in order to evaluate the issue price of a longevity bond of 25 years maturity. As an application, we propose a method to quantify the speed of mortality improvement by the average mean reverting times of the processes.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.332-332
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• 2017

Rice ratooning is the cultural practices to produce easily second rice from the stubble left behind after the main-crop harvest. The main advantage of rice ratooning is that in areas where rice is the main crop, double crop of rice can be grown for additional returns. Three early ripened rice cultivars were tested for estimation their milled rice quality and starch characteristics from main and ratoon rice. The main crop was harvested at mass maturity, after which the tillers were mowed to stubbles of about 10 cm tall. And then it left without any further input until the ratooned plant was ready for harvest. Highly significant variations were detected in the milled rice quality between main and ratoon rice. Protein and amylose contents of ratoon rice were more increased than those of main rice. The Toyo value (gloss) of cooked rice of ratoon crop was measured also higher than that of main crop. It resulted from higher air temperature during grain ripening compared with that of ratoon crop. The mean temperature during ripened period of ratoon rice was favorable for optimal maturation for early ripened rice cultivars. Normalized chromatograms of branch chain length distribution of amylopectin are demonstrated a distinct difference between main and ratoon rice flour. Ratoon rice had higher amount of short chains than that of main crop rice starches. Microscopic examination of rice flours with scanning electron microscopy shows starch granule shapes affected by the cropping types, main and ratoon rice. It showed significant differences among rice starch granule shapes and in granule size between main and ratoon rice. Starch of ratoon rice had more neat and smaller granules than that of main rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.255-262
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• 1997

To estimate the total dry matter(TDM) of rice plant by non-destructive method, spectral reflectance from rice plant canopy was measured by using the spectroradiometer (LI-1800, LICOR Inc.) with one week interval during the rice growing season at Suwon paddy field in 1993. Two medium late maturing rices, Daechung-byeo Ilpum-byeo, and one early maturing variety, Jinbu-byeo, were cultured to observe TDM, then they were compared with those estimated by vegetation index together. Vegetation index determined by the reflectance of visible against near infrared wavelength showed high correlation with TDM. Vegetation index derived from narrow band(10nm interval) ratio, R910/R460, has the highest correlation coefficient with TDM. TDM estimated from R910/R460 from transplanting to heading stage corresponded well to measured values (Y=21.2428X-212.734 ; $R^2$=0.87). But another vegetation index, NIR(720~1,100nm) /Red(600~700nm) showed higher correlation with TDM than NIR(720~1,100nm) /Blue(400~500nm) did from heading stage to maturity.