• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.13-21
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• 2022

Mushroom waste medium refers to the waste biomass generated after mushroom cultivating. And, the burden of treatment on mushroom farmhouse is increasing due to the absence of appropriate treatment method and increase of treatment costs of the mushroom waste medium. In this study, in order to assess the energy value of mushroom waste medium by an anaerobic digestion, methane potential and anaerobic organic matter decomposition characteristics were investigated. The theoretical methane potential(B_th) of mushroom medium(MM) was 0.481 Nm³-CH₄/kg-VS_added, and the B_th of mushroom waste medium(MWM) was 0.451 Nm³-CH₄/kg-VS_added. The biochemical methane potential(B_u-exp) of MWM was increased by 18% from 0.155 for MM to 0.183 Nm³-CH₄/kg-VS_added for MWM. In the reaction kinetics analysis by the Modified Gompertz model, the maximum methane production rate(R_m) was increased from 4.59 for MM to 7.21 mL/day for MWM and the lag growth phase time(λ) was decreased from 2.78 for MM to 1.96 days for MWM. In the reaction kinetics analysis by the parallel first order kinetics model, the easily degradable organic matter(VS_e) content was increased by 5.89% and the persistently degradable organic matter(VS_p) content was 2.03% in MWM, and the non-degradable organic matter(VS_NB) content was decreased by 7.85%. Therefore, it was evaluated that the anaerobic digestion efficiency of MWM was increased. The anaerobic digestion efficiency of MWM was assessed to be more improved than that of MM.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.436-446
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• 2015

It is suggested investigating method about the existing state of demand in this study. The total demand of 357 water amenity zones in 2014 is estimated based on the growth curve models. The effects of population density and distances between water amenity zones and metropolises populated over 1 million are investigated on each river system. The suitability like RMSE and MAPE of logistic and gompertz models are considered to select more suitable model for each water amenity zone. Demand for water amenity zones in 2014 is seemed to be rather high at Han Gang river system and Chungcheongbukdo after analyzing. The influence of population density is rarely effective except Geum Gang river system. The influence of metropolis on the demand for water amenity zones is higher at Geum Gang river system than others.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.1-14
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• 2020

Purpose - The propose of this study is to examine the effect of human development index on mobile telephony diffusion. Design/methodology/approach - This study fits the modidensity of South Asian Association for Regional Cooperation (SAARC) member countries with an econometric Gompertz growth model. The diffusion factors, including the human development index (HDI), gross domestic product (nominal) per capita, fixed-line telephony subscription, and population data of each member country from 2005 to 2018 are considered for the empirical experiment. Furthermore, the mobidensity of randomly sampled countries with very high human development scores (the Republic of Korea, Switzerland and Norway) and high development scores (Brazil and Costa Rica) have been examined with the same process as SAARC members. Findings - We have found a positive but insignificant relationship between the HDI value and mobile telephony diffusion in Afghanistan, Bangladesh, Bhutan, India, and Pakistan; a positive and statistically significant relationship at a 99% confidence level in SriLanka; and a negative and insignificant relationship in the Maldives and Nepal. HDI has both positive and negative effects on mobile telephony diffusion, with the nature of effect depending on the profiles of each country. HDI is a diffusion determinant of mobile telephony only for the high human development country groups. Research implications or Originality - This study provides a reference for policymakers, telecommunication stakeholders, and future researchers to design the telecommunication policies and strategies.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.21-30
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• 1997

The present study reports the density, growth and production of a razor clam, Sinollovacula constricta, which is known to be one of the important fishreies catches from the Korean tidal flat. The annual yield reached to about 6,000 metric tons per year till 1994. The study was conducted on the Hwaseong tidal flat located on the central west coast, 40 kilometers south-west from Seoul. The annual yield of the razor clam in this area reached to about 50% of the total catch from the whole Korean coast. Samples were colleted monthly at 14 occasions from May 1992 to August 1993. Density of S. constricta ranged from 92~165 individuals per square meter during the study period. General trend of decreasing density was observed when the animal became older, but an exception was the year class of 1991 whose density was lower than that of 1990. The size of the shell was clearly separated into two classes during fall and winter (from September to February), however, the maximum frequency of the length of small size classes moved to right after February. It indicates a fast growth of young clams from spring to summer. Fast growth of the shell could also be examined by the growth curve. The shell growth of the whole life span was described by the von Bertalanffy equation of $L_t=89.3{\times}[1{\exp}\{-0.58{\times}(t+0.73\}]$. The growth in flesh dry weight was well fitted to the Gompertz growth model with the equation, $W_t=5.00{\times}{\exp}\{-4.31{\times}{\exp}(-0.043{\times}t)\}$. The clam lost about 30% of the body weight during spawning in August. The annual production calculated based on the data from September 1992 to August 1993 amounted to 150 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ which was 2~50 fold higher than those of other bivalves occurred in Korea. This estimate was patitioned by each year classes; 87.5 by 1992, 53.4 by 1991, 59.0 by 1990 and -30.0 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ by 1989 year class.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.432-438
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• 2017

Objective: The objective of this study was to evaluate the effect of combinations of $NaNO_2$ and NaCl concentrations on Listeria monocytogenes (L. monocytogenes) growth in emulsion-type sausage. Methods: Emulsion-type sausages formulated with different combinations of $NaNO_2$ (0 and 10 ppm) and NaCl (1.00%, 1.25%, and 1.50%) were inoculated with a five-strain L. monocytogenes mixture, and stored at $4^{\circ}C$, $10^{\circ}C$, and $15^{\circ}C$, under aerobic or vacuum conditions. L. monocytogenes cell counts were measured at appropriate intervals, and kinetic parameters such as growth rate and lag phase duration (LPD) were calculated using the modified Gompertz model. Results: Growth rates increased (0.004 to 0.079 Log colony-forming unit [CFU]/g/h) as storage temperature increased, but LPD decreased (445.11 to 8.35 h) as storage temperature and NaCl concentration increased. The effect of combinations of NaCl and low-$NaNO_2$ on L. monocytogenes growth was not observed at $4^{\circ}C$ and $10^{\circ}C$, but it was observed at $15^{\circ}C$, regardless of atmospheric conditions. Conclusion: These results indicate that low concentrations of $NaNO_2$ and NaCl in emulsion-type sausage may not be sufficient to prevent L. monocytogenes growth, regardless of whether they are vacuum-packaged and stored at low temperatures. Therefore, additional techniques are necessary for L. monocytogenes control in the product.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1323-1329
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• 2005

A mathematical model was developed for predicting the growth kinetics of Listeria monocytogenes in tryptic soy broth (TSB) as a function of combined effects of temperature, pH, and NaCl. The TSB containing four different concentrations of NaCl (2, 4, 5, and $10\%$) was initially adjusted to six different pH levels (pH 5, 6, 7, 8, 9, and 10) and incubated at 4, 10, 25, or 37$^{circ}C$. In all experimental variables, the primary growth curves were well fitted ($r^{2}$=0.982 to 0.998) to a Gompertz equation to obtain the lag time (LT) and specific growth rate (SGR). Surface response models were identified as appropriate secondary models for LT and SGR on the basis of coefficient determination ($r^{2}$=0.907 for LT, 0.964 for SGR), mean square error (MSE=3.389 for LT, 0.018 for SGR), bias factor ($B_{1}$B,=0.706 for LT, 0.836 for SGR), and accuracy factor ($A_{f}$=1.567 for LT, 1.213 for SGR). Therefore, the developed secondary model proved reliable predictions of the combined effect of temperature, NaCl, and pH on both LT and SGR for L. monocytogenes in TSB.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.65-73
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• 2018

This study was carried out for 20 days in a bio-drying batch reactor under the blowing conditions of 0.75, 1.00, 1.25, and $1.50L/min{\cdot}kg$ in order to optimize the operating conditions for the bio-drying of food wastes. The decomposition rate of organic matter during the bio-drying operation period was analyzed using modified Gompertz model. The maximum organic degradation (P) was 2.31, 2.52, 2.27 and 1.88 kg at air flow rates of 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, and the maximum organic degradation rate was 0.33, 0.45, 0.28, and 0.18 kg/day at 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively, showing excellent organic decomposition efficiency at a air flow rate of $1.00L/min{\cdot}kg$. The lag growth phase time (${\lambda}$) of the bio-drying reactor was 2.10, 1.48, 1.15, and 1.06 days at 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively. The water removal rate in the operation of bio-drying reactor of food waste increased with the increase of air flow rate from the early stage of bio-drying to the middle stage, and the highest water removal rate was observed at the air flow rate of $1.00L/min{\cdot}kg$ at the end of bio-drying. The optimum air flow rate condition of bio-drying reactor was $1.00L/min{\cdot}kg$.

• International Area Studies Review
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• v.13 no.3
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• pp.331-359
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• 2009

We forecast the performance of the Korean biotechnology industry by adopting similar development paths taken by the U.S. biotechnology and Korean ICT industries. Our long-term forecasting techniques predict that Korean BT market size will increase from 3.7 billion to 10.8 billion U.S. dollars by year 2030. The pharmaceutical industry, one of major bio-subindustries, is expected to dominate Korean BT market in the long-run. Also, the relative portion of the exports in the Korean BT industry will be larger and thus the export-oriented government policy is required for the long-run growth of the Korean BT industry. Since the Korean ICT industry has already slowed down in the development, Korean BT industry is likely to catch up with ICT industry in the near future.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.503-508
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• 2004

This study was conducted to estimate the growth curve parameters of crossbreds between Korean native boars and Landrace sows and their relationships with meat qualities. The data used were weight-age data and carcass data from 131 males and 122 females raised at N.L.R.I in Korea. Growth curve parameters were estimated from nonlinear regression using Gompertz model individually. Average mature weight(A), average maturing rate(k), and average inflection point(u) showing maximum growth rate estimated were 179.54${\pm}$6.06kg, 0.3154${\pm}$0.0059, and 5.50${\pm}$0.11 months in females, and 179.84${\pm}$6.33kg, 0.3049${\pm}$0.0061, and 5.24${\pm}$0.13 months in males, respectively. For the growth curve parameters and derived statistics, the phenotypic correlations of maturing rate with gain rate at inflection, mature weight, and inflection point were - .30, - .77, and - .93 in male, and - .31, - .78 and - .94 in female, respectively. Matrure weight was positively correlated to the inflection point as + .89 in both male and female, indicating that late maturing pigs with lower k had longer maturing period with increasing gain rate and reached point of inflection later than early maturing pigs with higher k, and grew to larger mature weight. Backfat thickness and erode fat contents were correlated with mature weight positively in male and negatively in female, and correlated with gain rate at inflection point positively in both male and female, of which coefficients were as high as .42 and .50 in male, respectively.