• Asian Journal of Innovation and Policy
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• v.12 no.3
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• pp.363-382
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• 2023

This study aims to discern the determinants influencing the perception of workability among the elderly population and delineate an appropriate retirement age within the labor market context. Employing binary logistic regression, this research utilizes data from the Korea Welfare Panel Study (2008, 2012, 2016, and 2020) provided by the Korea Institute for Health and Social Welfare. The findings indicate that key factors shaping the elderly's perception of workability encompass familial responsibilities (household and marital status) and their levels of physical and mental well-being. Econometric analysis suggests an anticipated retirement age for the elderly population ranging between 67 and 69 years. In addressing labor market demands and informing policymakers, the study proposes deliberations on extending the retirement age for individuals aged 60 to 65. This range serves as a compromise between the identified retirement age of 67 to 69 and the current average retirement age for elderly labor market participants. Bridging the disparity between the perceived workability age and the prevailing labor market baseline is crucial for achieving social consensus. Therefore, any extension of the retirement age should carefully consider both the demand and supply perspectives within the labor market. The study's contribution lies in two main aspects: firstly, presenting a retirement age framework for the labor market that integrates the workability of the elderly population, and secondly, providing evidence-based research outcomes to guide informed labor policies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.608-616
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• 2018

If a general nonlinear system is linearized by the successive multiplication of the 1st and 2nd order systems, then there are four types of poles in this linearized system: the pole of the 1st order system and the equal poles, two distinct real poles, and complex conjugate pair of poles of the 2nd order system. Linear Quadratic (LQ) control is a method of designing a control law that minimizes the quadratic performance index. It has the advantage of ensuring the stability of the system and the pole placement of the root of the system by weighted matrix adjustment. LQ control by the weighted matrix can move the position of the pole of the system arbitrarily, but it is difficult to set the weighting matrix by the trial and error method. This problem can be solved using the characteristic equations of the Hamiltonian system, and if the control weighting matrix is a symmetric matrix of constants, it is possible to move several poles of the system to the desired closed loop poles by applying the control law repeatedly. The paper presents a method of calculating the state weighting matrix and the control law for moving the equal poles with Jordan blocks to two real poles using the characteristic equation of the Hamiltonian system. We express this characteristic equation with a state weighting matrix by means of a trigonometric function, and we derive the relation function (${\rho},\;{\theta}$) between the equal poles and the state weighting matrix under the condition that the two real poles are the roots of the characteristic equation. Then, we obtain the moving-range of the two real poles under the condition that the state weighting matrix becomes a positive semi-finite matrix. We calculate the state weighting matrix and the control law by substituting the two real roots selected in the moving-range into the relational function. As an example, we apply the proposed method to a simple example 3rd order system.

• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.101-106
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• 2005

Objectives : We conducted this study to examine the association between serum GGT levels within the normal range and the risk factors of cardiovascular diseases Methods : We examined the cross-sectional association between serum GGT and the systolic and diastolic blood pressure, fasting blood glucose, total cholesterol, triglyceride, high density lipoprotein cholesterol (HDLcholesterol), and uric acid among 975 subjects that participated in the health examination of a university hospital located in Daegu city. All the patients' GGT levels were within the normal range. Results : After adjustment were made for age, body mass index (BMI), smoking status, drinking frequency, exercise frequency and coffee intake, the serum GGT level was positively associated with fasting blood glucose (p<0.01), total cholesterol (p<0.01), and triglyceride (p<0.01) in men, and it was positively associated with fasting blood glucose (p<0.01), total cholesterol (p<0.05), triglyceride (p<0.01), and uric acid (p<0.01) in women. The associations were not significantly different depending on the status of alcohol drinking or obesity, except for the associations of serum GGT with diastolic blood pressure (P for interaction=0.04) and uric acid (P for interaction=0.04) between the lean and obese subjects. Conclusions : Serum GGT levels within the normal range were positively associated with fasting blood glucose, triglyceride and uric acid in most subgroups irrespective of the drinking or obesity status. These results suggest that GGT has important clinical implications as being more than just a marker of alcohol consumption and hepatobiliary disease.

• Journal of Chest Surgery
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• v.41 no.3
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• pp.354-359
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• 2008

Background: Warfarin is used as an anticoagulant and it is mainly excreted by the liver metabolism (the R-form is mainly metabolized by cytochrome p450 3A4, and the S form by cytochrome p450 2C9). Rifampin is usually used for tuberculosis or endocarditis, and it is a representative drug that induces the CYP families, including 3A4 and 2C9. The anticoagulation effect of warfarin decreases through the increased metabolism that's due to the induction of enzymes, and this iscaused by rifampin when patients take these two medicines together. No one has suggested appropriate guidelines regarding this drug interaction even though an appropriate adjustment of warfarin's dosage is needed. We examined the drug interaction in patients who received warfarin-rifampin combination therapy according to the time interval, and the factors affecting drug interaction were analyzed. Based on the data, we tried to determine the clinically available warfarin dosage guidelines before and after taking this drug combination. Material and Method: We reviewed the OO University Hospital anticoagulation service team's follow up sheets that were filled out from Jan '1998 to Sep 2006 for the patient who took warfarin - rifampin combination therapy (n=15). Result: The average INR of all the patient before rifampin administration was $2.25{\pm}0.52$ $(mean{\pm}SD)$, and that value for the first 100 days after rifampin administration was $1.98{\pm}0.28$. The p value for these two sets of data showed no correlation (paired t-test, p>0.05). The average INR of all the patient before rifampin cessation was $2.19{\pm}0.34$, and the value after rifampin cessation was $2.49{\pm}0.43$. The p value of these two showed correlation (paired t-test, p<0.05) but the average INR falls between the therapeutic INR range. Conclusion: The warfarin dose adjustment equation of before and after warfarin-rifampin combination therapy was derived based on this study's results because the warfarin dosage adjustment of the anticoagulation service team was considered appropriate.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.363-370
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• 2023

Various earth observation satellites need to provide accurate and high-quality data after launch. To maintain and enhance the quality of satellite data, it is crucial to employ a cross-calibration process that accounts for differences in sensor characteristics, such as the spectral band adjustment factor (SBAF). In this study, we utilized Landsat-8 and Sentinel-2A satellite imagery collected from desert sites in Libya4, Algeria3, and Mauritania2 among pseudo-invariant calibration sites to calculate and apply SBAF, thereby compensating the uncertainties arising from variations in bandwidths. We quantitatively compared the reflectance differences based on the similarity of bandwidths, including Blue, Green, Red, and both the near-infrared (NIR) narrow, and NIR bands of Sentinel-2A. Following the application of SBAF, significant results with reflectance differences of approximately 1% or less were observed for all bands except NIR. In the case of the Sentinel-2A NIR band, it exhibited a significantly larger bandwidth difference compared to the NIR narrow band. However, after applying SBAF, the reflectance difference fell within the acceptable error range (5%) of 1-2%. It indicates that SBAF can be applied even when there is a substantial difference in the bandwidths of the two sensors, particularly in situations where satellite utilization is limited. Therefore, it was determined that SBAF could be applied even when the bandwidth difference between the two sensors is large in a situation where satellite utilization is limited. It is expected to be helpful in research utilizing the quality and continuity of satellite data.

• Journal of KIISE
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• v.42 no.10
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• pp.1254-1267
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• 2015

Recently, excessive installations of APs have caused WLAN interference, and many techniques have been suggested to solve this problem. The AP aggregation technique serves to reduce active APs by moving station connections to a certain AP. Since this technique forcibly moves station connections, the transmission performance of some stations may deteriorate. The AP transmit power control technique may cause station disconnection or deterioration of transmission performance when power is reduced under a certain level. The combination of these two techniques can reduce interference through AP aggregation and narrow the range of interferences further through detailed power adjustment. However, simply combining these techniques may decrease the probability of power adjustment after aggregation and increase station disconnections upon power control. As a result, improvement in performance may be insignificant. Hence, this study suggests a scheme to combine the AP aggregation and the AP transmit power control techniques in OpenFlow-based WLAN to ameliorate the disadvantages of each technique and to reduce interferences efficiently by performing aggregation for the purpose of increasing the probability of adjusting transmission power. Simulations reveal that the average transmission delay of the suggested scheme is reduced by as much as 12.8% compared to the aggregation scheme and by as much as 18.1% compared to the power control scheme. The packet loss rate due to interference is reduced by as much as 24.9% compared to the aggregation scheme and by as much as 46.7% compared to the power control scheme. In addition, the aggregation scheme and the power control scheme decrease the throughput of several stations as a side effect, but our scheme increases the total data throughput without decreasing the throughput of each station.

• Food Science and Preservation
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• v.13 no.2
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• pp.259-268
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• 2006

We investigated food preservation hurdles used for Korean traditional side dishes. As a first step of the research preparation and cooking recipes of the side dishes were surveyed, which are commonly used in Korean households. As next step, compositional and microbial quality attributes were measured onto the samples collected from the market. Antimicrobial ingredient added in the preparation are reasoned to work as important hurdles based on the scientific principles. Heating processes such as blanching, boiling, braising, hard-boiling and frying help to keep the produce decontamination or water activity adjustment. Measured salt contents of most side dishes were in the range of 1-5% with those of salt-preserved vegetables being higher. pH values were 4.7-6.4 with those of salt-preserved vegetables being lower and those of hard boiled fishes being higher. Soluble solids of braised or hard-boiled dishes were usually above $40^{\circ}Brix$, while those of blanched and seasoned vegetables had lower values. Water activity values were 0.93-0.95 for seasoned vegetables and 0.77-0.88 for hard-boiled or semi dried beans and seafoods. Product with processing steps of braising or blanching showed lower bacterial load of 102-104 cfu/g, while seasoned or salt-preserved vegetables and seafoods had aerobic bacterial count above 106 cfu/g. Korean traditional side dishes were found to apply the appropriate combinations of heating preparation process, water activity and pH adjustment and salting, providing the required preservation properties.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.65-86
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• 1990

Living conditions of the rural elderly were assessed in terms of clothing behavior, health and nutritional status, housing and envioronmental condition, and psychological adjustment. The subjects were eighty individuals over sixty residing in the rural community of Iksan-kun, Chollabukdo. The interview method using questionnaires, direct measurement, and observation was used for this study. Data were compared with those obtained from a previous study of the elderly residing in an urban area. Clothing behavior showed that the elderly residing in the rural community were more concerned about plain and conservative design of clothes than their urban counterparts. Special protective clothes for cropdusting with agricultural chemicals had not been prepared. The following urgent needs were pointed out: development and supply of agricultural chemical protective clothing and development and education of appropriate washing and clothing care methods. The health status of the elderly was generally good, but poor eating habits were found more frequently in the rural elderly than among the urban dwellers. Several dietary nutrient intakes were insufficient. Contrasting the urban elderly with the rural group, it was found that the urban group lacked sufficient vitamin A and vitamin C and the urban women had insufficient calorie whereas the rural group was deficient in protein, vitamin A, calorie, and fat. A significant relationship was found between dietary nutrient intake and health index, food habit points, self recognized health status, meal satisfaction, and economic status. Urgent needs of the development of a nutrition education program for the elderly were pointed out. Most of elderly residing in the surveyed rural communities were living alone or with their spouse only, therefore only one room was used among the three or four available rooms. Most of the rural elderly were living either in a traditional Korean house built with differing floor levels or in a modified Korean style house. Minimal modernization had been made for kitchen facilities such as sink and gas range or for heating facilities with the briquette boiler. However, sanitary space such as lavatory and bathroom had not been remodeled. A housing welfare program for rural communities should be implemented at the national level. The comparison of psychological characteristics of the rural elderly with their city counterparts revealed that the rural elderly have a more stable psychological status and optimistic attitude than those living in a city. However, it was found that most of the elderly did not have any future plan. Community programs for the elderly including hobbies or leisure activities or education programs to generate close interpersonal relationships with their children should be developed and provided.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1032-1032
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• 2001

Artificial Neural Network (ANN) calibration techniques have been used commercially for agricultural applications since the mid-nineties. Global models, based on transmission data from 850 to 1050 nm, are used routinely to measure protein and moisture in wheat and barley and also moisture in triticale, rye, and oats. These models are currently used commercially in approx. 15 countries throughout the world. Results concerning earlier European ANN models are being published elsewhere. Some of the findings from that study will be discussed here. ANN models have also been developed for coarsely ground samples of compound feed and feed ingredients, again measured in transmission mode from 850 to 1050 nm. The performance of models for pig- and poultry feed will be discussed briefly. These models were developed from a very large data set (more than 20,000 records), and cover a very broad range of finished products. The prediction curves are linear over the entire range for protein, fat moisture, fibre, and starch (measured only on poultry feed), and accuracy is in line with the performance of smaller models based on Partial Least Squares (PLS). A simple bias adjustment is sufficient for calibration transfer across instruments. Recently, we have investigated the possible use of ANN for a different type of NIR spectrometer, based on reflectance data from 1100 to 2500 nm. In one study, based on data for protein, fat, and moisture measured on unground compound feed samples, dedicated ANN models for specific product classes (cattle feed, pig feed, broiler feed, and layers feed) gave moderately better Standard Errors of Prediction (SEP) compared to modified PLS (MPLS). However, if the four product classes were combined into one general calibration model, the performance of the ANN model deteriorated only slightly compared to the class-specific models, while the SEP values for the MPLS predictions doubled. Brix value in molasses is a measure of sugar content. Even with a huge dataset, PLS models were not sufficiently accurate for commercial use. In contrast an ANN model based on the same data improved the accuracy considerably and straightened out non-linearity in the prediction plot. The work of Mr. David Funk (GIPSA, U. S. Department of Agriculture) who has studied the influence of various types of spectral distortions on ANN- and PLS models, thereby providing comparative information on the robustness of these models towards instrument differences, will be discussed. This study was based on data from different classes of North American wheat measured in transmission from 850 to 1050 nm. The distortions studied included the effect of absorbance offset pathlength variation, presence of stray light bandwidth, and wavelength stretch and offset (either individually or combined). It was shown that a global ANN model was much less sensitive to most perturbations than class-specific GIPSA PLS calibrations. It is concluded that ANN models based on large data sets offer substantial advantages over PLS models with respect to accuracy, range of materials that can be handled by a single calibration, stability, transferability, and sensitivity to perturbations.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.625-637
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• 2003

This study was performed to examine the relationship between air pollution exposure and mortality in Seoul for the years of 1998∼2001. Daily counts of death were analyzed by general additive Poisson model, with adjustment for effects of seasonal trend, air temperature, humidity, and day of the week as confounders in a nonparametric approach. Daily death counts were associated with CO (current day),O$_3$ (current day), PM$_{10}$ (current day), NO$_2$ (1 day before), SO$_2$ (1 day before). Increase of 41.71 $\mu\textrm{g}$/㎥ (interquartile range) in PM$_{10}$ was associated with 1.3% (95% CI = 0.7∼1.9％) increase in the daily number of death. $O_3$ concentrations resulted in an increased risk of 1.3% for 23.86 ppb in all-aged mortality [RR = 1.013 (1.004-1.023)1. This effect was greater in children (less than 15 aged) and elderly (more than 65 aged). After ozone level exceeds 25 ppb, the dose-response relationship between mortality and ozone was almost linear. We concluded that Seoul had 1∼5％ increase in mortality in association with IQR (interquartile range) in air pollutants. Daily variations in air pollution within the range currently occurring in Seoul might have an adverse effect on daily mortality. These findings also support the hypothesis that air pollution, at levels below the current ambient air quality standards of Korea, is harmful to sensitive subjects, such as children or elderly.rly.