• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2923-2934
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• 2009

This paper presents study on technological forecasting of Next-Generation Display technology. Next-Generation Display technology is one of the emerging technologies lately. So databases on patent documents of this technology were analyzed first. And patent analysis was performed for finding out present technology trend. And the forecast for this technology was made by growth curves which were obtained from forecast models using patent documents. In previous study, Gompertz, Logistic, Bass were used for forecasting diffusion of demand in market. Gompertz, Logistic models which were often used for technological forecasting, too. So, two models were applied in this study. But Gompertz, Logistic models only consider internal effect of diffusion. And it is difficult to estimate maximum value of growth in two models. So, Bass model which considers both internal effect and external effect of diffusion was also applied. And maximum value of growth in Gompertz, Logistic models was estimated by Bass model.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.25-30
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• 2011

In this study, predictive mathematical models were developed to predict the kinetics of Listeria monocytogenes growth in the mixed fresh-cut vegetables, which is the most popular ready-to-eat food in the world, as a function of temperature (4, 10, 20 and $30^{\circ}C$). At the specified storage temperatures, the primary growth curve fit well ($r^2$=0.916~0.981) with a Gompertz and Baranyi equation to determine the specific growth rate (SGR). The Polynomial model for natural logarithm transformation of the SGR as a function of temperature was obtained by nonlinear regression (Prism, version 4.0, GraphPad Software). As the storage temperature decreased from $30^{\circ}C$ to $4^{\circ}C$, the SGR decreased, respectively. Polynomial model was identified as appropriate secondary model for SGR on the basis of most statistical indices such as mean square error (MSE=0.002718 by Gompertz, 0.055186 by Baranyi), bias factor (Bf=1.050084 by Gompertz, 1.931472 by Baranyi) and accuracy factor (Af=1.160767 by Gompertz, 2.137181 by Baranyi). Results indicate L. monocytogenes growth was affected by temperature mainly, and equation was developed by Gompertz model (-0.1606+$0.0574^*Temp$+$0.0009^*Temp^*Temp$) was more effective than equation was developed by Baranyi model (0.3502-$0.0496^*Temp$+$0.0022^*Temp^*Temp$) for specific growth rate prediction of L.monocytogenes in the mixed fresh-cut vegetables.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.223-229
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• 2006

In this study, we have conducted kinetics and modelling studies of Centella asiatica cell growth and substrate uptake, in an attempt to evaluate cell growth for a better understanding and control of the process. In our bioreactor cultivation experiment, we observed a growth rate of 0.18/day, a value only 20% higher than was seen in the shake flask cultivation trial. However, the observed maximum cell dry weight in the shake flask, 10.5g/L, was 14% higher than was achieved in the bioreactor. Ninety seven percentage confidence was achieved via the fitting of three unstructured growth models; the Monod, Logistic, and Gompertz equations, to the cell growth data. The Monod equation adequately described cell growth in both cultures. The specific growth rate, however, was not effectively predicted with the Logistic and Gompertz equations, which resulted in deviations of up to 73 and 393%, respectively. These deviations in the Logistic and Gompertz models may be attributable to the fact that these models were developed for substrate-independent growth and fungi growth, respectively.

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.4
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• pp.75-90
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• 2022

Purpose - This study aims to study the activation pattern of declining industries by applying the Gompertz growth model using available resources based on the theory of industrial life cycle, classifying declining industries among Korean manufacturing industries, and identifying resource input characteristics. Research design and methodology - This study was conducted by combining the Gompertz growth model that predicts the limit of output based on available resources under the industrial life cycle theory. Using Gompertz model, this study analyzed the life cycle of 39 Korean manufacturing industries from the perspective of domestic production, number of employees, and fixed assets Results - According to a life cycle analysis of 39 manufacturing industries in Korea, the computer, textile, and shoe industries were classified as declining industries. Among them, research on resource input characteristics on the shoe industry showed that domestic production and the number of employees decreased, while the proportion of domestic R&D personnel and the number of research departments gradually increased. Conclusion - Among the declining industries in Korea, the shoe industry is considered to revitalize the industry, that is, to extend the life of the declining industry by offshoring its production site and improving constitution with a "R&D center for global" support.

• The Journal of Economics, Marketing and Management
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• v.11 no.1
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• pp.31-44
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• 2023

Purpose: This study aims to figure out the characteristics of corporate life cycle and resource input in terms of the sustainability diagnosis of pharmaceutical companies in Korea. Research design, data, and methodology: Using the Gompertz model under the assumption that companies have finite resources, this study tries quantitative interpretation of life cycle and resource input pattern for longevity companies with 25 years of experience among 158 pharmaceutical companies listed on Korean stock market based on maturity of revenue. Results: The study found revenue maturity through Gompertz model was statistically correlated with enterprise value. According to the life cycle analysis, more than 95% of 59 pharmaceutical companies were in the growth and maturity phase and have an average life cycle of 88 years and an average remaining life of 52 years. Regarding maturity profile of resource input, maturity of employees was generally high more than 60% and this meant there was jobless growth in Korean pharmaceutical industry. Conclusion: This study demonstrated there is a high statistical correlation between the maturity of a company's resource input and its revenue and enterprise value. It is believed that these results could be utilized as a basis for high fidelity function that predict revenue and enterprise value based on resource input information.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.157-165
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• 2016

Among high-tech products, the mobile phone has experienced a rapid rate of innovation and a shortening of its product life cycle. The shortened product life cycle poses major challenges to those involved in the creation of forecasting methods fundamental to strategic management and planning systems. This study examined whether the best model applies to the entire diffusion life span of a mobile phone. Mobile phone sales data from a specific mobile service provider in Korea from March of 2013 to August of 2014 were analyzed to compare the performance of two S-shaped diffusion models and two non-linear regression models, the Gompertz, logistic, Michaelis-Menten, and logarithmic models. The experimental results indicated that the logistic model outperforms the other three models over the fitted region of the diffusion. For forecasting, the logistic model outperformed the Gompertz model for the period prior to diffusion saturation, whereas the Gompertz model was superior after saturation approaches. This analysis may help those estimate the potential mobile phone market size and perform inventory and order management of mobile phones.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.362-368
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• 2006

A pot experiment was conducted to investigate the effects of soil burial depth on seedling emergences of rice (Oryza sativa) and Echinochloa spp. and to model such effects for mathematical prediction of seedling emergences. When the Gompertz curve was fitted at each soil depth, the parameter C decreased in a logistic form with increasing soil depth, while the parameter M increased in an exponential form and the parameter B appeared to be constant. The Gompertz curve was combined by incorporating the logistic model for the parameter C, the exponential model for the parameter M, and the constant for the parameter B. This combined model well described seedling emergence of rice and Echinochloa species as influenced by soil burial depth and predicted seedling emergence at a given time after sowing and a soil burial depth. Thus, the combined model can be used to simulate seedling emergence of crop sown in different soil depths and weeds present in various soil depths.

• Electronics and Telecommunications Trends
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• v.17 no.3 s.75
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• pp.80-86
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• 2002

본 연구는 현재 통신서비스 산업에서 가장 많이 사용하고 있는 5개 예측모형(단순 성장 모형, 단순 Logistic 모형, Gompertz 모형, 확장 Bass 모형, 시간 변동 Bass 모형)을 이용한 초고속 인터넷 가입자에 대한 예측력을 비교 평가하는 데 있다. 예측모형의 추정 방법으로 비선형 회귀방정식(nonlinear regression)을 사용하여 추정의 효율성을 높였다. 예측력 비교분석 기준은 (i) 포화점에 대한 타당성 (ii) 모수에 대한 통계적 유의성 (iii) 실제치 대비 예측치에 대한 AAD 기준을 통하여 예측모형의 예측력을 비교 평가하였다. 본 연구에서 실시한 방법론에 따라 다섯 가지 통신서비스 예측모형의 예측력을 분석한 결과 가장 작은 AAD를 나타낸 예측모형은 Log-Logistic 모형으로 나타났으며, 가장 큰 AAD를 나타낸 예측모형은 단순 Logistic 모형으로 나타났다. 또한 AAD 기준에서 보면 일반적으로 많이 사용하고 있는 Gompertz 예측모형과 Bass 모형 중에서는 Gompertz 예측모형이 더 우월한 것으로 나타났다.

• Communications for Statistical Applications and Methods
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• v.30 no.5
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• pp.467-483
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• 2023

In this research, a conversion function and a distortion associated with the conversion function are defined and used to derive a unit power Gompertz distortion. A new family of copulas is built using the global distorted function. Four base copulas, namely Clayton, Gumbel, Frank, and Gaussian, are distorted into the family. Some properties including tail dependence coefficients and tail order are examined. Kendall's tau formula is derived for new copulas when the base copula is Clayton, Gumbel, or Frank. The maximum pseudo-likelihood estimation method is employed, and a simulation study was performed. The log-likelihood and AIC are reported to compare the performance of the fitted copulas. According to the applied data, the results indicate that new distorted copulas with additional parameters improve the fit.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.356-362
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• 2010

This research studied the bio-methane potential of several waste biomass materials as alternative sources for biogas production, and the laboratory procedure for measuring the biochemical methane potential was described. The wastes from four agro-industries (sewage, livestock, food wastewater treatment sludge and cattle rumen substance generating in slaughter house) were evaluated as substrates for the assay of biochemical methane potential. In order to estimate the ultimate methane yield, two empirical equations (modified Gompertz equation and exponential equation) was investigated. The ultimate methane yield of sewage, livestock, food sludge and lumen substance estimated by the modified Gompertz equation were 0.086, 0.147, 0.146, and 0.121 L $CH_{4}\;g^{-1}\;VS_{added}$, respectively. The ultimate methane yield estimated by the exponential equation were 0.109, 0.246 and 0.174 L $CH_{4}\;g^{-1}\;VS_{added}$ in sewage, livestock sludge and lumen substance. And the ultimate methane yield estimated by the exponential equation showed more high values in the range of 26.7 ~67.3% than the ultimate methane yield estimated by the modified Gompertz equation.