• Korean Journal of Ecology and Environment
• /
• v.42 no.1
• /
• pp.39-47
• /
• 2009

Spatial and temporal analysis of water quality was performed for eleven monitoring stations in Dongjin River watershed in order to determine the trends of monthly water quality. The monthly water quality data of biochemical oxygen demand (BOD), total nitrogen (TN) and total phosphorus (TP) during $1995{\sim}2004$, were analyzed utilizing Seasonal Mann-Kendall test, LOWESS and three-dimensional graphic approaches. The results indicated that BOD and TN concentrations had the downward trend, but TP showed the upward trend, especially in Gobucheon. This numerical and graphic analysis is the useful tool to analyze the long-term trend of water quality in a large river system.

• Membrane and Water Treatment
• /
• v.10 no.5
• /
• pp.339-352
• /
• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• Journal of Animal Science and Technology
• /
• v.63 no.1
• /
• pp.180-190
• /
• 2021

This study aimed to determine the carcass and meat quality of broiler chickens based on the slaughter age (28, 30, 32, and 34 days). The carcass characteristics included live and carcass weights, carcass rate, dressing rate, and retail cut weight. The meat quality properties were determined through proximate composition, pH, color, water holding capacity (WHC), cooking yield, and shear-force. The broiler chicken live, carcass, breast, thigh, and wing weights significantly increased with the slaughter age (p < 0.05); the tenderloin weight also exhibited a similarly increasing trend. However, the carcass rate of the day 28 sample was significantly lower than the other samples (p < 0.05). The protein and ash contents of the breast exhibited an increasing trend with increasing slaughter age. The protein content of the thigh of the day 28 sample was significantly lower than that of the other samples (p < 0.05), while the ash contents of the day 28 and 30 samples were significantly lower. The redness of the breast showed an increasing trend, and the pH and lightness of the thigh exhibited a decreasing trend with slaughter age. The WHC and cooking yields of the day 30 and 32 breast and thigh samples were significantly higher than those of the day 28 and 34 samples (p < 0.05). The breast and thigh shear-force of the day 30-34 samples were significantly higher than those of the day 28 sample (p < 0.05). The present study showed that even with a twoday difference in slaughter age, the broiler chicken meat quality showed a significant difference in several characteristics.

• Health Policy and Management
• /
• v.30 no.1
• /
• pp.131-138
• /
• 2020

The purpose of this study was to compare the health status of South Korea with those of Organization for Economic Cooperation and Development (OECD) countries and examine the trends. Position vAlue for Relative Comparison (PARC) was used as a gauge for comparison, and five sectors of the health care system were measured: demand, supply, accessibility, quality, and cost. The Mann-Kendall test was used as a statistical analysis method to examine trend of PARC values obtained from 2000 to recent years. According to the results, the demand, supply, accessibility, and quality sectors were higher than the OECD average, while the cost was lower than the average. However, there is a recent trend of sharp increases in health care costs. Some indicators: health employment, quality of primary care and mental health care were lower than the OECD average, and health determinants showed a worsening trend. Therefore, policy-makers need to take this into account and make efforts for sustainable health care.

• Journal of Digital Convergence
• /
• v.13 no.2
• /
• pp.141-151
• /
• 2015

As smartphone penetration increases are mobile payments service are expanding. Mobile Commerce software market is trend that is soaring. Accordingly, high reliability Mobile Commerce request of high quality are enlarged. And The greater amount of data is going to be more mobile commerce market situation is also gradually increased. In this paper, I surveyed and analysed the general trend and test/certification trend of mobile commerce software, and developed the mobile commerce software quality evaluation metrics base on ISO/IEC 9126 and ISO/IEC 12119, the standard about the quality evaluation.

• Journal of Korean Society on Water Environment
• /
• v.27 no.1
• /
• pp.120-128
• /
• 2011

Korea Groundwater Quality Monitoring Network is a database of annual groundwater quality survey results to prevent groundwater pollution. We estimated contamination index (CI) values for each type of land use, and analyzed temporal trends of pollutant concentration data in the Groundwater Quality Monitoring Network from 2001 to 2009. Among the pollutants considered in the database, the concentrations of nitrate and chloride were higher than their standards. In the case of nitrate, recreation parks, golf courses and general waste dumping regions showed increasing trends according to linear regression analysis, whereas industrial complexes and residential regions of urgan and recreation parks showed increasing trends in the chloride concentration data. According to multiple variable linear regression analysis, EC, pH and topography were major factors influencing CI values. These results suggest that groundwater with a high CI value and increasing trend is vulnerable for potential contamination, which requires more careful groundwater pollution control.

• Journal of Korean Society for Quality Management
• /
• v.23 no.3
• /
• pp.93-101
• /
• 1995

We present a brief survey concerning the relations between mean residual life and failure rate. Change points of mean residual life and failure rate are known to be different in general and we explore such situations in this paper. A few parametric models which show bathtub-shaped failure rate are examined in details, including the shape of its corresponding mean residual life function. We give some graphical comparisons of trend changes of mean residual life and failure rate for various choices of parameters for each parametric model.

• Asian Journal of Atmospheric Environment
• /
• v.11 no.4
• /
• pp.235-253
• /
• 2017

This study was conducted for analyzing the contribution factors on ozone concentrations and its long term trends in each major city and province in Korea through several statistical methods such as simple linear regression, generalized linear model, KZ-filer, correlation matrix, Kringing method, and cluster analysis. The overall ozone levels in South Korea have been consistently increasing over the past 10 years. The ozone concentrations in Seoul, the biggest city in Korea, are the lowest in all areas with the highest increasing ratio for $95^{th}%$ ozone. It is thought that the active photochemical reaction could affect the higher ozone concentration increase. On the other hand, the ozone concentrations in Jeju are the highest in Korea with the highest increasing ratio for $5^{th}%$, $33^{th}%$, and $50^{th}%$ ozone. It is also thought that the weak $NO_x$ titration could be the reason of higher ozone concentrations in Jeju. In case of Jeju, transport related factors is the major factor affecting the ozone trend. Thus, it is assumed that the variation of ozone trend of Asian region affecting the ozone trend in Jeju, where domestic ozone photochemical reaction is less active than urban area. It is thought that the photochemical reaction plays the role of increasing of ozone concentrations in the urban area, even though the LRT affected on the increase of ozone concentrations in non-urban area.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.192-193
• /
• 2015

Construction Cycle Trend Survey, which survey total value of orders and realized amounts monthly, is a valuable statistics that used to quick grasp or forecast the trend of domestic construction business. In recent periodical survey quality diagnoses, few professional users named a problem that Construction Cycle Trend Survey could not get together with the current state of the construction industry. This study examined weather Construction Cycle Trend Survey reflects the economic sentiment of construction business or not. Paired t test was performed between Construction Cycle Trend Survey and Construction Business Survey Index (CBSI), and significant differences were verified.

• Journal of Korean Society for Quality Management
• /
• v.47 no.3
• /
• pp.597-613
• /
• 2019

Purpose: The purpose of this study is to analyze the trend of quality research by analyzing the entire JKSQM(Journal of the Korean Society for Quality Management). Methods: This study is to analyze the frequency of words used in the abstract of the all JKSQM by applying the text mining processing. We use wordcrowd among text mining techniques. Results: 22 words of high frequency were presented in the abstract of the paper published in the JKSQM for 42 years. The frequency of words was shown on a 10 year basis, and the four important words were plotted on a change graph for each Vol. Frequent words of each Vol. are added in the appendix. Conclusion: The main research results are as follows. First, there has been no significant change in research trends over the last 40 years. Second, the early SQC words have been widely used, and since 1990, many words such as service-oriented words have been used, indicating a change in the times. Third, the use of the words of the 4th industrial revolution since 2010 is weak. In the above analysis, the trend of quality research in Korea is within the quality category and can be considered conservative. Now, it is expected that everything will be changed in the period of the 4th Industrial Revolution, and it is time to study the direction of quality in Korea.