• Journal of The Korean Astronomical Society
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• v.50 no.2
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• pp.21-27
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• 2017

The autoregressive method provides a univariate procedure to predict the future sunspot number (SSN) based on past record. The strength of this method lies in the possibility that from past data it yields the SSN in the future as a function of time. On the other hand, its major limitation comes from the intrinsic complexity of solar magnetic activity that may deviate from the linear stationary process assumption that is the basis of the autoregressive model. By analyzing the residual errors produced by the method, we have obtained the following conclusions: (1) the optimal duration of the past time for the forecast is found to be 8.5 years; (2) the standard error increases with prediction horizon and the errors are mostly systematic ones resulting from the incompleteness of the autoregressive model; (3) there is a tendency that the predicted value is underestimated in the activity rising phase, while it is overestimated in the declining phase; (5) the model prediction of a new Solar Cycle is fairly good when it is similar to the previous one, but is bad when the new cycle is much different from the previous one; (6) a reasonably good prediction of a new cycle can be made using the AR model 1.5 years after the start of the cycle. In addition, we predict the next cycle (Solar Cycle 25) will reach the peak in 2024 at the activity level similar to the current cycle.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.6
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• pp.59-72
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• 2002

Along with the enlargement of WTO, issues about standardization activity are more and more become concerning object worldwide. Countries launch the work that putting the standardization in order, such as re-establishing their standardization strategy. With the chance of entering WTO, China is promoting the rebuilding of standardization system in order to conform to international standardization system. Thus, in this paper, research make it clear that the variation of circumstance of standardization activity, the importance of the standardization activity, and the international movement, in the meantime, it surveyed the development course of standardization activity and it's present operating system. By this means, it concludes the problems of present operating system and implies the improving scheme. Further more, this paper implies Chinese characteristic standardization system which conform with WTO/TBT and international standardization system. Firstly, through the comprehensive analysis on standardization system, it figures out the main function of relevant organizations in each working stage. Secondly, this paper makes a system model composed of possible three stage, and setup items needs promotion and main target in each stage. Finally, this paper point out the development direction of standardization system, it also implies it's limitation and the later possible research topic in this field.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1576-1585
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• 2018

Regularly participating in physical activity is known to improve quality of life and body composition in elderly with stroke. However, comparatively less physical activity is performed by the stroke survivors. The factors related to inactivity in elderly female stroke survivors have not been elucidated. Therefore, this study aims to compare the quality of life factors and limb compositions between the active and inactive elderly female stroke survivors. Forty nine subjects between the ages of 65 to 75 years were selected from the KNHANES data between the years 2009 to 2011. In addition, 186 agematched healthy peers were also selected for limb composition comparisons. The subjects were groups based on walking days per week: walkers; 3 days or more, non-walkers; less than 3 days per week. BMI and waist circumference were within the obesity ranges for both the non-walkers and walkers. As results, the trend for greater fat (${\pm}10%$) and lean mass (${\pm}30%$) differences were observed for non-walker and walkers, respectively. Significantly greater reasons for function limitation by stroke and hypertension were reported with significantly greater self-care difficulty was shown by the walkers. In conclusion, elderly female stroke survivals may require customized motivation and continuous support to participate in physical activity regularly.

• The Journal of Economics, Marketing and Management
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• v.5 no.2
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• pp.33-39
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• 2017

As the aging population geworsened by the a of the low fertility rate in the wake of the birth of the low birth rate, the rapid increase in the retirement age of the baby boomers in the wake of the birth of the Korean War is a significant indication of the separation of the aged and the role of the economically rich and the role of the role of the economically rich. Therefore, this study aims to address issues and countermeasures. The study aims to provide basic data for the future life of the baby boom generation by examining the problems and responses to the economic activity after the retirement activity of the baby boomers. The research suggests that the limit was limited to the retirement age of the baby boomer generation in order to boost the employment of the elderly. Due to the lack of exploration of the exploratory research, the lack of analysis of exploratory facts is the biggest limitation of the analysis. So, further analysis of this will lead to meaningful studies. Looking at the composition of this study, the introduction of the study included the necessity and purpose of the study. The focus on the point was on the concepts and characteristics of the baby boomer, and analyzed the characteristics of the economic activity and analyses and analyses of domestic and international cases. In conclusion, the issue was drawn up and the alternatives were sought.

• Korean journal of food and cookery science
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• v.23 no.1 s.97
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• pp.90-98
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• 2007

The purpose of this study was to apply the activity-based costing (ABC) model to restaurant menu costing. The overhead cast of six entr${\acute{e}}$es in XYZ restaurant was calculated for all levels of activity. When comparing activity-based costing with traditional costing applied to BBQ pork rib and an assorted seafood platter, the total difference of costs between two items was 2,191 won in activity-based costing and 600 won in traditional costing. The average food cast percentage of the six entr${\acute{e}}$es was 27% using traditional costing, while the average activity-based cost percentage was 40%. Therefore, there was a 13% difference between the actual margin volume and the expected margin volume. The application of activity-based costing to the restaurant industry would be a milestone from a cost point of view as well as from a process point of view. In particular, the limitation that traditional costing only accounts for food costs could be overcome b considering the overhead cost as an important part of the cast structure. Furthermore, activity-based costing would not only help to reduce the costs associated with the process of analyzing the activities but it would also provide more accurate cost information for menu pricing.

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.73-79
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• 2011

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

• KIEAE Journal
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• v.4 no.2
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• pp.37-40
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• 2004

New visible photocatalyst(Nanovis$^{(R)}$) has been synthesized to overcome the barrier of limitation of UV light utilization of current $TiO_2$ photocatalyst. It was found that red shift of absorption spectrum to 550nm was achieved. Its physical properties were characterized by XRD, BET and TEM. It is also observed that Nanovis$^{(R)}$ has a photocatalytic activity for photodegradation of Trichloroethylene under visible light irradiation. V,VII group doped into substitutional sites of $TiO_2$ has proven to be indispensable for band-gap narrowing and photocatalytic activity. These test results lead us to conclude that Nanovis$^{(R)}$ can be used for IAQ improvemen and for photocatalytic water splitting to hydrogen.

• Journal of Chest Surgery
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• v.22 no.3
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• pp.448-455
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• 1989

Till June 1988, We experienced 3 cases of single atrium at Dept. of Thoracic k Cardiovascular Surgery of National Medical Center. Case 1 was 26 years old female, and had single atrium associated with partial cleft in mitral anterior leaflet and PAPVC. Atrial septation with Dacron patch and MVR [I-S, 31 mm] were done, followed by TAP, De Vega. Postoperative course was good, OPD follow-up for about 4 years with normal physical activity and ordinary working. Case 2 was 4 years old female with single atrium alone. Atrial septation with pericardial patch. Good postoperative course and OPD follow-up for about 2 years with appropriate physical growth. Case 3 was 22 years old female, single atrium with complete cleft in the anterior and posterior mitral leaflet, and septal tricuspid cleft were identified. Atrial septation with polystan bovine pericardial patch and repair of mitral anterior cleft. Postoperatively, residual regurgitation of mitral and tricuspid valve, but tolerable in some limitation of physical activity.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.27-39
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• 2018

Since the global positioning system (GPS) has been included in mobile devices (e.g., for car navigation, in smartphones, and in smart watches), the impact of personal GPS log data on daily life has been unprecedented. For example, such log data have been used to solve public problems, such as mass transit traffic patterns, finding optimum travelers' routes, and determining prospective business zones. However, a real-time analysis technique for GPS log data has been unattainable due to theoretical limitations. We introduced a machine learning model in order to resolve the limitation. In this paper presents a new, three-stage real-time prediction model for a person's daily route activity. In the first stage, a machine learning-based clustering algorithm is adopted for place detection. The training data set was a personal GPS tracking history. In the second stage, prediction of a new person's transient mode is studied. In the third stage, to represent the person's activity on those daily routes, inference rules are applied.

• The Korean Journal of Health Service Management
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• v.12 no.4
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• pp.139-154
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• 2018

Objectives: The aim of this study was to examine factors influencing health-related quality of life of waged workers. Methods: This study used data from the Seventh Korea National Health and Nutrition Examination Survey. Data were analyzed with the $x^2-test$, t-test, ANOVA, and multiple regression. Results: The significant predictors of health-related quality of life were depression, subjective health status, age, activity limitation, education, worker status, monthly income, drinking, smoking, physical injury, stress, and moderate physical activity. Conclusions: Personal health characteristics, psychological characteristics, socioeconomic characetrictics and working characetrictics affect health-related quality of life. Health-related quality of life is also affected by social structural problems such as socioeconomic factors and employment instabilitye. In addition to the development of health care programs to improve health-related quality of life of twaged workers, policy changes are needed to improve the social structure.