• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.509-516
• /
• 2020

Since the 1960s, many rivers have been polluted and destroyed due to river repair projects for economic development and the covering of small rivers due to urbanization. Many studies have analyzed rivers using measured river topographic factors, but surveying is not easy when the flow rate changes rapidly, such as during a flood. In addition, the previous research has been mainly about the cross section of a river, so information on the longitudinal profile is insufficient. This research used informational entropy theory to obtain an equation that can calculate the average river slope, river slope, and river longitudinal elevation for a river basin in real time. The applicability was analyzed through comparison with measured data of a river's characteristic factors obtained from a river plan. The parameters were calculated using informational entropy theory, nonlinear regression analysis, and actual data. The longitudinal elevation entropy equation for each stream was then calculated, and so was the average river slope. All of the values were over 0.96, so it seems that reliable results can be obtained when calculating river characteristic factors.

• Korea journal of population studies
• /
• v.33 no.3
• /
• pp.1-30
• /
• 2010

This study examines difference in age at marriage between spouses and more importantly, investigates into the economic and social factors affecting the ratio or probability of wife-older marriages. Empirical analysis is carried out by applying both logit model and multinomial logit model to an independently pooled cross-section over 2004-2007. The data was collected mainly from the micro data service system of the Statistics Korea. Empirical results indicate that a wife-older marriage was more likely as a wife was more educated and was a larger income earner than a husband. On the other hand, a wife's educational and income level themselves had few systematic relationships with the probability of a wife-older marriage. The probability of a wife-older marriage tended to decrease(increase) when a husband's(a wife's) marriage was the second' The study calculates the average marginal effect of difference in the income level between spouses on the probability of a wife-older marriage, which is -0.007. That is, the probability of a wife-older marriage increases by 0.7% as a husband's income level is 1 million Korean Won less than a wife's. This results presents empirical evidence against widely distributed misconception on wife-older marriage in the mass media.

• Journal of Korea Society of Industrial Information Systems
• /
• v.13 no.1
• /
• pp.76-86
• /
• 2008

This paper estimates the TFP in IT manufacturing (total factor productivity) by employment size of establishment and analyses the determinants of it. And the panel data is consisted of time series and cross section data of 4 employment size of establishment over $1990{\sim}2004$. During the period from 1991 to 1997 TFP increased positively irrespective of the employment size of establishment, but from 1998 to 2004 TFP increase rate turned negative except large size(more than 300) of establishment. TFP assume macro variables and policy variables as the determinants of IT manufacturing TFP. The analysis of whole size of establishment shows that sales growth rate is significantly positive, which makes us conclude that there is a teaming by doing effect and economy of scale. But some variables(i.e. IT capital stock, policy financing, and openness etc.) are significant in only a few models. So there may be different effect by employment size of establishment. In TFP determinants analysis by employment size of establishment, we find that coefficients of policy financing and openness variables are significantly positive. The larger employment size of establishment is, the larger scale economy is. And for large size(more than 300) establishment, IT capital stock helps propel the increase of the productivity.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.16 no.3
• /
• pp.201-217
• /
• 2014

There is likely to be a fit problem when women aged in their 30s-40s purchase down-age clothing from brands that target women in their 20s. To identify the part of the lower body that causes the fit problem, the sizes and types of lower body of women in their 30s-40s were compared with those of women in their 20s. The data for this study was from the 2010 Size Korea survey of body measurements of 1675 female adults in their 20s-40s. To examine differences in the average sizes of the lower body between women in their 20s and 30s-40s, descriptive statistics and t-tests were conducted. Factor and cluster analysis were used to classify body types by age groups. On the whole, compared to women in their 30s-40s, women in their 20s were found to be higher for all height items and smaller for size, thickness and width items. The result of the Glycemic index analysis showed that the body type of women in their 20s was generally larger than that of women in their 30s-40s. In addition, women in their 20s had a large drop value compared to those in their 30s-40s, whereas flatness of body cross section was bigger in the group of women in their 30s-40s. Four factors related to the lower body type of female adults in their 20s-40s were identified in the factor analysis, and three categories of body type were identified by cluster analysis. A Type 1 individual had abdominal obesity and chubby lower limbs, Type 2 had short legs and slightly chubby lower limbs, and Type 3 had long legs and a skinny lower body. A significant number of women in their 30s-40s were included in the Type 1 group, which was the least common category for women in their 20s.

• Korean Journal of Social Welfare
• /
• v.68 no.2
• /
• pp.213-232
• /
• 2016

The purpose of this study is to explore the stress profile that adolescent perceives by using Latent Profile Analysis (LPA), and to examine the effect of characteristics variable per groups that appeared in profile. By using the cross-section data of 'A survey on the human right of Korean children and adolescent in 2013' issued by National Youth Policy Institute, the LPA concerning the stress type was conducted and surveyed 9,521 adolescents from fourth grade in elementary school to seniors in high school nationwide. The result of this study shows that two class types were selected according to the goodness-of-fit index and latent class classification rate. Type 1 is named low-risk group as they show low level, whereas type 2 is named relative risk group as they show high level. In order to predict the characteristics of adolescent stress, the study conducted Binary Logistic Regression analysis on the basis of low-risk group. There is higher probability to belong to relative risk group, the more they are female students than male students, the less their subjective health condition and happiness, the more runaway experience, the less school grades and the less economic affluence in their household. The implication of this research, its limitation and direction of follow-up research were suggested.

• Journal of Korea Water Resources Association
• /
• v.48 no.5
• /
• pp.367-377
• /
• 2015

ADCPs have been highlighted so far for measuring steramflow discharge in terms of their high-order of accuracy, relatively low cost and less field operators driven by their easy in-situ operation. While ADCPs become increasingly dominant in hydrometric area, their actual measurement accuracy for velocity and bathymetry measurement has not been sufficiently validated due to the lack of reliable bench-mark data, and subsequently there are still many uncertain aspects for using ADCPs in the field. This research aimed at analyzing inter-comparison results between ADCP measurements with respect to the detailed ADV measurement in a specified field environment. Overall, 184 ADV points were collected for densely designed grids for the given cross-section that has 6 m of width, 1 m of depth, and 0.7 m/s of averaged mean flow velocity. Concurrently, ADCP fixed-points measurements were conducted for each 0.2m and 0.02m of horizontal and vertical spacing respectively. The inter-comparison results indicated that ADCP matched ADV velocity very accurately for 0.4~0.8 of relative depth (y/h), but noticeable deviation occurred between them in near surface and bottom region. For evaluating the capacity of measuring bathymetry of ADCPs, bottom tracking bathymetry based on oblique beams showed better performance than vertical beam approach, and similar results were shown for fixed and moving-boat method as well. Error analysis for velocity and bathymetry measurements of ADCP can be potentially able to be utilized for the more detailed uncertainty analysis of the ADCP discharge measurement.

• Korean Journal of Remote Sensing
• /
• v.34 no.3
• /
• pp.481-494
• /
• 2018

The accurate radiative transfer model simulation is essential for an accurate ozone profile retrieval using optimal estimation from backscattered ultraviolet (BUV) measurement. The input parameters of the radiative transfer model are the main factors that determine the model accuracy. In particular, meteorological parameters such as temperature and surface pressure have a direct effect on simulating radiation spectrum as a component for calculating ozone absorption cross section and Rayleigh scattering. Hence, a sensitivity of UV ozone profile retrievals to these parameters has been investigated using radiative transfer model. The surface pressure shows an average error within 100 hPa in the daily / monthly climatological data based on the numerical weather prediction model, and the calculated ozone retrieval error is less than 0.2 DU for each layer. On the other hand, the temperature shows an error of 1-7K depending on the observation station and altitude for the same daily / monthly climatological data, and the calculated ozone retrieval error is about 4 DU for each layer. These results can help to understand the obtained vertical ozone information from satellite. In addition, they are expected to be used effectively in selecting the meteorological input data and establishing the system design direction in the process of applying the algorithm to satellite operation.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.24 no.6
• /
• pp.390-399
• /
• 2012

This research observed the cross section current of 7 survey lines in Seokmo Channel of Gyeonggi bay with a lot of freshwater inflow and S-shaped for 13 hours during flood season and neap tide. We indicated the distribution of the current velocity by comprehending the speed and direction of the current velocity of each line during maximum flood, ebb tide and observed the distribution of salinity. Moreover, in order to understand what lateral momentum causes the lateral flow in each survey line, we practiced the momentum analysis through the observation data. As a result, the lateral baroclinic pressure gradient force and vertical friction of the Seokmo channel during neap tide were the strongest, and this is why the flow by the distribution of salinity and stratification most often occurs. In north of the Seokmo channel, where have wide intertidal and a lot of freshwater inflow, the secondary circulation is caused by balance of lateral baroclinic pressure gradient force and other forces, and the vertical friction was strong in the lines with small depth. On the other hand, in the southern part of the Seokmo channel where the water is deep and the waterway is curved, the advective acceleration and centrifugal force become stronger by the geographical causes during ebb and the influence of fresh water. Therefore, the lateral flow in the Seokmo channel was caused by the distribution of the momentum that differs by location, depth, curve, etc.

• Journal of Korean Society of Forest Science
• /
• v.85 no.4
• /
• pp.557-564
• /
• 1996

Based on stem analysis as well as branch analysis data of each tree from 8 plots of circle clear-cutting and 1 biomass plot in Changbai Mountain area, located in Northeast of China, the effective crown form of Changbai larch(Larix olgensis H.) plantation were studied by using the approach of crown curve. The results indicated that the cross-section forms of effective crown were stable and showed approximate circle for different tree size. Because the effective crown was on upper position of the canopy and its form reflects crown architecture under non-competition condition, the architecture is mainly affected by species hereditary feature. Therefore, for the specified species the effective crown form was thought to be relatively stable. The effective crown form of tree was neither related to the tree size within stand nor to the stand condition for different stand. The total effective crown curve of larch plantation could be characterized by using mean effective crown taper.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.520-525
• /
• 2019

Mines are an important infrastructure for securing resources, but safety problems can arise in the course of operation. Recently, the mining process is very complicated due to the large scale and mechanization. Therefore, it is necessary to construct accurate geospatial information on mine for systematic and safe mine operation. The geospatial information construction using the existing total station has a disadvantage that a lot of work time is required because the target must be collimated and measured. In this study, the data of the mines were acquired with the total station and the 3D laser scanner, and the mine spatial information was constructed by using the shape based registration method. By using the static scanner data of some area applying the reference point surveying result of the total station, it was possible to construct the accurate result on the wide area acquired by the mobile scanner effectively. Also, the accuracy of the constructed geospatial information was evaluated and the deviation of mean 0.083m was shown. Point cloud products constructed through the research can contribute to the efficiency improvement of mine management by enabling quantitative analysis such as visualization of mine shape, distance, area and slope, and automation of drawing creation for cross section shape.