• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.483-486
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• 2020

Age estimation and gender classification for human is a classic problem in computer vision. Almost research focus just only one task and the models are too heavy to run on low-cost system. In our research, we aim to apply multitasking learning to perform both task on a lightweight model which can achieve good precision on embedded system in the real time.

• International Journal of Reliability and Applications
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• v.18 no.1
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• pp.9-20
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• 2017

In this paper, we consider a renewable repair-replacement warranty strategy with age-dependent minimal repair service and propose an optimal maintenance model during post-warranty period. Such model implements the repair time limit under warranty and follows with a certain form of system maintenance strategy when the warranty expires. The expected cost rate is investigated per unit time during the life period of the system as for the standard for optimality. Based on the cost design defined for each failure of the system, the expected cost rate is derived during the life period of the system, considering that a renewable minimal repair-replacement warranty strategy with the repair time limit is provided to the customer under warranty. When the warranty is finished, the maintenance of the system is the customer's responsibility. The life period of the system is defined and the expected cost rate is developed from the viewpoint of the customer's perspective. We obtain the optimal maintenance strategy during the maintenance period by minimizing such a cost rate after a warranty expires. Numerical examples using field data are shown to exemplify the application of the methodologies proposed in this paper.

• Korean Journal of Exercise Nutrition
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• v.24 no.1
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• pp.9-13
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• 2020

[Purpose] This preliminary study aimed to develop a regression model to estimate the resting metabolic rate (RMR) of young and middle-aged Koreans using various easy-to-measure dependent variables. [Methods] The RMR and the dependent variables for its estimation (e.g. age, height, body mass index, fat-free mass; FFM, fat mass, % body fat, systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, and resting heart rate) were measured in 53 young (male n = 18, female n = 16) and middle-aged (male n = 5, female n = 14) healthy adults. Statistical analysis was performed to develop an RMR estimation regression model using the stepwise regression method. [Results] We confirmed that FFM and age were important variables in both the regression models based on the regression coefficients. Mean explanatory power of RMR₁ regression models estimated only by FFM was 66.7% (R²) and 66.0% (adjusted R²), while mean standard errors of estimates (SEE) was 219.85 kcal/day. Additionally, mean explanatory power of RMR₂ regression models developed by FFM and age were 70.0% (R²) and 68.8% (adjusted R²), while the mean SEE was 210.64 kcal/day. There was no significant difference between the measured RMR by the canopy method using a metabolic gas analyzer and the predicted RMR by RMR₁ and RMR₂ equations. [Conclusion] This preliminary study developed a regression model to estimate the RMR of young and middle-age healthy Koreans. The regression model was as follows: RMR₁ = 24.383 × FFM + 634.310, RMR₂ = 23.691 × FFM - 5.745 × age + 852.341.

• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.133-141
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• 2012

As we move from the industrial age to the information age, domestic industries are changing rapidly, and rural society is also laying the foundation to make use of information technologies. Through this kind of modernization, the size of agricultural facilities has been increasing on a significant scale. But, in reality, there are many difficulties in the maintenance of agricultural facilities in proportion to their growing number. Accordingly, this research aims to solve the fundamental problems that occur with agricultural facilities in the maintenance stage. In addition, it aims to provide information on how to maintain and manage facilities for farmers. The presentation of the maintenance information was conducted using a case-based reasoning method that solves current problems based on past cases. The tool of case-based reasoning was applied to define the establishment of the base for cases, characteristic variables and maintenance measures. The effectiveness of a CBR model was examined through the case study. The use of the case-based reasoning method is judged to be effective as a tool to support the decisions of farmers regarding maintenance. When the maintenance measures derived through the CBR model are offered to farmers, the fundamental problems of maintaining agricultural facilities will be solved, and the damage to such facilities minimized.

• Anatomy and Cell Biology
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• v.56 no.4
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• pp.474-481
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• 2023

The dental characteristics created by acquired dental treatments can be used as age estimators. This pilot study aimed to analyze the correlation between the number of teeth observed for dental characteristics and chronological age and to develop new non-invasive age estimation models. Dental features on panoramic radiographs (420 radiographs of subjects aged 20-89 years) were classified and coded. The correlation between the number of teeth for each selected code (codes V, X, T, F, P, and L) and age was observed, and multiple regression was performed to analyze the relationship between them. Eleven regression models with various combinations of dental sextants were presented. The model with the data from both sides of the posterior teeth on both jaws showed the best performance (root mean square error of 14.78 years and an adjusted R² of 0.461). The model with all teeth was the second-best. Based on these results, we confirmed statistically significant correlations between certain dental features and chronological age. We also observed that some regression models performed sufficiently well to be used as adjunctive methods in forensic practice. These results provide valuable information for the design and performance of future full-scale studies.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.61-71
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• 2017

The tracer gas method has an advantage that can estimate total and local ventilation rate by tracing air flow. However, the field measurement using tracer gas has disadvantages such as danger, inefficiency, and high cost. Therefore, the aim of this study was to evaluate ventilation rate in pig house by using the thermal distribution data rather than tracer gas. Especially, LMA (Local Mean Age), which is an index based on the age of air theory, was used to evaluate the ventilation rate in pig house. Firstly, the field experiment was conducted to measure micro-climate inside pig house, such as the air temperature, $CO_2$ concentration and wind velocity. And then, LMA was calculated based on the decay of $CO_2$ concentration and air temperature, respectively. This study compared between LMA determined by $CO_2$ concentration and air temperature; the average error and root mean square error were 3.76 s and 5.34 s. From these results, it was determined that thermal distribution data could be used for estimation of LMA. Finally, CFD (Computational fluid dynamic) model was validated using LMA and wind velocity. The mesh size was designed to be 0.1 m based on the grid independence test, and the Standard $k-{\omega}$ model was eventually chosen as the proper turbulence model. The developed CFD model was highly appropriate for evaluating the ventilation rate in pig house.

• Journal of the Korean Home Economics Association
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• v.29 no.2
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• pp.241-248
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• 1991

The aim of this study is to propose the criteria for a evaluation model of the lifetime household work and organize the model. The results were as follows: Three criteria for a evaluation model of the life-time household work were proposed. $\circled1$ An appropriate framework of the evaluation model should be based on the transition of the family life. $\circled2$ The model should include major variables influencing the value of household work of homemaker. $\circled3$ The model should be flexible enough to accommodate various evaluation methods, and should reflect idiosyncracies of different evaluation methods. In view of the criteria stated above, the present study is based on the family life cycle framework. And the age of the last offspring exhibits a consistent major influence in the evaluation based on the household work hours, while the education level of homemakers shows a consistent major influence in the evaluation based on household worker. So as to reflect these two major variables in the family life cycle framework.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.19-27
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• 2017

This study investigated to predict the compressive strength of unsaturated polyester resin based polymer concrete using the maturity method. The test results show that the development of the compressive strength increased exponentially until an age of 24 hours. After 24 hours, the development of the compressive strength just increased gradually. This test result shows that the strength of unsaturated polyester resin based polymer concrete was developed mainly at the early age. Estimated datum temperature of unsaturated polyester resin based polymer concrete was $-20.67^{\circ}C$ which was much lower than of datum temperature ($-10^{\circ}C$) of Portland cement concrete. Also, this study result shows that the existing maturity index associated with Portland cement concrete was not applicable for polymer concrete because curing time of Portland cement concrete is different clearly with curing time of polymer concrete. The cause of different curing time was that there were different curing mechanisms between Portland cement concrete and polymer concrete. In order to best apply the experimental data to a model, CurveExpert Professional, the commercial software, was used to determine the predictive model regarding the compressive strength of unsaturated polyester resin based polymer concrete. As a result, Gompertz Relation or Weibull Model was an appropriate model as a predictive model. The proposed model can be used to predict the compressive strength, especially, it is more useful when the maturity is in the range between $40^{\circ}C{\cdot}h^{0.4}$ and $900^{\circ}C{\cdot}h^{0.4}$.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.11-18
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• 2005

In order to accurately assess the stresses occurring in the early-age concrete, a compliance function which can consider the characteristics of early-age concrete is required. Existing compliance functions, however, have the limit that they have been deduced from the data of hardened concrete and therefore, do not take into account the fast development of material properties in early-age concrete. Furthermore, the distinction between instantaneous compliance and creep compliance is not clear in the existing experimental method. The purpose of present study is to propose a compliance function which can describe the rapid change of hardening processes in early-age concrete. To this end, a test method which can estimate the instantaneous compliance without creep effects in the early-age concrete was suggested first. Based on the suggested experimental method, tests on the instantaneous as well as creep compliance were performed using MTS automatic servo-loop test machine. The test results showed that both instantaneous and aging viscoelastic compliance, which are constants in B3 model, were functions in terms of age of concrete especially at early ages. Therefore, the modified compliance function based on B3 model was proposed to provide more realistic prediction on the behavior of early-age concrete. It is expected that the present model allows more realistic evaluation of varying stresses in concrete structures at early ages.

• Korean Journal of Adult Nursing
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• v.27 no.6
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• pp.624-633
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• 2015

Purpose: This study was to develop and test a theoretical model based on the revised health belief model explaining osteoporosis prevention behaviors among postmenopausal women under 65. Methods: This secondary data analysis included 342 postmenopausal women under 65 from original data sources of a total of 734 women. The measured instruments were scales for osteoporosis awareness, osteoporosis health belief scale (benefit, barrier, susceptibility, severity, and health motivation), self-efficacy, and osteoporosis prevention behaviors. Data were analyzed using SPSS/WIN 20.0 and AMOS 20.0. Results: The mean age of the subjects was 55.2 years and the mean age of menopause was 51.10. The hypothetical model of osteoporosis prevention behaviors was relatively fit. Osteoporosis prevention behaviors were significantly explained up to 62% by expectation factors (relative benefit, self-efficacy, health motivation) and modifying factors(knowledge only). Expectation factors of health belief had a mediation effect between modifying factors and prevention behaviors. Conclusion: This study partially supported the revised health belief model for explaining osteoporosis prevention behaviors. It provides a basis for developing an educational program focusing on expectation factors and knowledge with the aim of behavioral changes for osteoporosis prevention.