• Journal of Labour Economics
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• v.41 no.3
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• pp.1-59
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• 2018

The Earned Income Tax Credit (EITC) is a policy that supports low-income households financially as well as provides an economic incentive to participate in the labor market. Thus, estimating the causal effect of the policy on the labor force participation rate of low-income households is critical for the policy evaluation. In this paper, we exploit the variation in the eligibility to the EITC and the size of the benefit over several reforms of the EITC in South Korea since 2008 and estimate the impact on the participation in the labor market. Using data from four major household surveys, we find that the results are mixed; in some samples and specifications, we find that the effect is positive and statistically significant, while it is insignificant in others. The estimated effect is more likely to be positive and significant when we restrict the sample to the period before 2014. It is an important topic of future research whether the EITC's effect gets weaker because it is extended to cover the self-employed and beneficiaries of the National Basic Livelihood Security.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10607-10611
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• 2015

Background: HER2 expression in the primary tumor and its lymph node metastases vary in gastric cancer, reflecting intratumoral heterogeneity. This finding also suggests that proliferation of a different clone in metastatic nodes is possible. In the current study, we aimed to determine the cause of discordance in HER-2 expression in the primary tumor and lymph node metastases for patients with gastric cancer. Materials and Methods: Eighty-one patients with gastric cancer who had undergone radical gastrectomy and were found to have lymph node metastasis upon pathological examination were included. Histopathological samples were obtained from biopsies obtained during patient gastrectomies and lymph node dissection. HER2 status was evaluated by both immunohistochemistry (IHC) and silver in situ hybridization (SISH). Results: Sixty-four (79%) patients were SISH (-), while 17 (21%) were SISH (+) in the primary tumor. However, in metastatic lymph nodes, HER2 status was SISH positive in 5 (28.3%) of the 64 SISH (-) primary tumor specimens. One of the 17 SISH (+) primary tumors was SISH (-) in the metastatic lymph nodes. Thus, SISH results for HER2 in both primary tumors and lymph node metastases were comparable, showing a concordance of 92.5%. In total, six patients demonstrated discordance between the primary tumor and lymph node metastases. The prevalence of HER2 discordance was significantly higher for patients in the pN2 and N3 stages (p=0.007). Although discordant patients had worse survival rates than concordant patients, the differences were not significant (p>0.05).Conclusions: Our study indicates that the frequency of concordance in HER2 status, as determined by IHC or SISH, is high in primary tumors and their corresponding lymph node metastases for patients with gastric cancer. If there is a discrepancy in HER2 status, its evaluation by both IHC and SISH may be useful for detecting patients who would benefit from trastuzumab, and it would therefore help guide decision-making processes in administering treatment.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.1
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• pp.79-89
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• 1999

Recent expansion of urban parks has been partly successful in terms of providing urban outdoor recreation space. Unfortunately we paid very little attention to the importance of providing regional identity to urban parks until recently. Thus one of the most important tasks of the contemporary landscape architects of Korea is to investigate ways to improve regional identity of urban parks. This study is aimed at evaluating how well the current urban parks have realized their own regional identity. To test the effectiveness of the concept of 'identity', the identity items were created, while a research model was developed by using such variables as in urban park identity, park satisfaction, belongingness to the region, and residential satisfaction. In order to test the model, the causations were analyzed. Meanwhile, the scales to evaluating identity were reviewed by means of the unstructures group interview, and were finally determined as 10 items; culture, uniqueness, symbolic, historic nature, homogeneity, harmony, difference, public benefit, nativeness and traditionality. Data from three new towns in the capital region-Bundang, Ilsan and Sanbon-were collected, and their central parks were referred to a questionnaire survey. The data were processed using descriptive statistics, correlation analysis, multiple regression analysis and path analysis. It was found through this survey that subjects 'sentiments regarding the sample towns' regional identity differed slightly. Residents of Bundang felt the strongest amount of regional identity, followed by those of Ilsan and Sanbon. In addition, the most important scale on regional identity is 'park satisfaction', followed by 'belongingness to the region' and 'residental satisfaction'. The path analysis was conducted to interpret the causations in a more detailed and comprehensive way than correlation analysis. As a result, it was proven that the regional identity affects 'belingingness to region' through the intermediated variable 'park satisfaction', while affecting ' residential satisfaction' through the intermediate variables 'park satisfaction' and 'beligningness to region'. In other words, although the regional identity of a park does not directly affect 'belongingness to region' or 'residental satisfaction', it has indirect effects on them through intermediate variables.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.10-18
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• 2014

This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2D
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• pp.103-110
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• 2012

This study presents O/D based emission estimation model and methodology under cold- and hot-start conditions. Contrasting with existing link-based model, new model is able to estimate cold-start emissions with actual traffic characteristics. The results of the case study with new model show similar amount of emission with existing model under hot-start conditions, but five times much more than existing model under cold-start conditions. The annual social benefit estimated by this model is 56.2 hundred million won, which is 48% higher than the result from existing model. It means current green transportation policies are undervalued in terms of air quality improvement. Therefore, New model is expected to improve the objectivity of air quality evaluation results regarding green transportation policies and be applied in various transportation-environment policies.

• Journal of the military operations research society of Korea
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• v.33 no.2
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• pp.75-86
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• 2007

This paper presents the overall valuation framework of the Army Tactical Command Information System(ATCIS) with its empirical data which is developed by the ROK Army in 2005 with its own R&D efforts over the past 10 years. The valuation with the appropriate methods is conducted through the full and relentless support of ROK Army HQs, defense agencies, and related firms. And the results include both qualitative and quantitative values of the ATCIS in perspectives of economic, technical, and defense strength effects. As a result, the development of ATCIS is valued over 1.7291 trillion Won which is over 6.55 times benefit and cost ratio comparing with other country's similar system. The worth of this paper includes the actual framework and methods to apply the valuation of other weapon systems and its preliminary research, defense offset valuation, performance evaluation and others.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.255-263
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• 2010

In order to prepare the interchange between and the unification of North and South Korea, it is needed to establish the development direction of irrigation reservoirs and formulate technological and political directions for preparing effectively against the demand of agricultural countermeasure information like the analysis of rural comprehensive development projects and the present state of agricultural land of North Korea. The purpose of this research is to construct the database of agricultural productive infrastructures and analyze the present state of irrigation reservoirs of the Yeseong River Basin in North Korea using SPOT-5 satellite imagery. As a result of the research, we were able to not only design classification items but establish method and precedure for producing thematic maps related agricultural productive infrastructure without on-site survey by analyzing present condition related to agricultural water of the basin. And we intend to provide basic data for analyzing suitabile locations of irrigation reservoirs in the basin by performing basin extraction, volume evaluation of the existing reservoirs, scale cultivative lands, benefit area fo the reservoirs, and the existing agricultural water system. In addition, we were able to understand the problem and limit in constructing the database related agricultural productive facilities.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.40-48
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• 2014

A number of attempts has been made to reinforce ballasted track substructure to meet the requirement of high-speed operation and effective rehabilitation of existing railroads. For the purpose of this, the use of geogrid has been applied, and the benefit of its use has been recognized via previous studies. In this study, an experimental pullout test was carried out to investigate the influence of normal stress on pullout strength of geogrid using different types of soil and geogrid. The results revealed that the pullout resistance generally tends to increase proportional to normal stress while the pullout coefficient interaction decreases, which is a function of material interface properties, such as the friction angle of soil, and interlocking condition between soil and geogrid. In addition, a methodology based on work-energy concept was proposed to evaluate effectiveness of geogrid and limitedly verified using test results.

• Journal of the Korean Society of Food Culture
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• v.31 no.5
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• pp.430-441
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• 2016

The purpose of this study was to determine the association between school administrator support as perceived by nutrition teachers (dietitians) and job satisfaction in order to provide data concerning efficient job performance of nutrition teachers, to determine effects of school administrator support on job satisfaction in nutrition teachers, and to provide basic data that could help improve school meals. Major supporters of nutrition teachers (dietitians) were chief administrators (55.3%), principals (27.2%), assistant principals (15.0%), and managers in charge (2.4%). Nutrition teachers (dietitians) scored 3.38 for perception of school administrator support, 3.66 for emotional support, 3.27 for informational support, 3.22 for instrumental support, and 3.11 for evaluation support. Support of nutrition teachers (dietitians) by school managers included emotional support (3.66)>informational support (3.27)>instrumental support (3.22)>evaluative support (3.11). Nutrition teachers (dietitians) scored 3.37 for job satisfaction, as follows: work performance (4.19)>interpersonal relationships (3.39)>job satisfaction in general (3.37)>job itself (3.29)>job environment (3.07)>performance rating and benefits system (2.70). Statistically significant correlation was observed between perception of school administrator support and job satisfaction (r= .771, p< .01). Therefore, school administrators are necessary to provide evaluative supports to nutrition teachers (dietitians), performance assessment, employee benefit packages, and improvement of school meal plans and quality.

• Journal of Gastric Cancer
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• v.15 no.4
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• pp.262-269
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• 2015

Purpose: Intraabdominal abscess is one of the most common reasons for re-hospitalization after gastrectomy. This study aimed to develop a model for estimating the probability of intraabdominal abscesses that can be used during the postoperative period. Materials and Methods: We retrospectively reviewed the clinicopathological data of 1,564 patients who underwent gastrectomy for gastric cancer between 2010 and 2012. Twenty-six related markers were analyzed, and multivariate logistic regression analysis was used to develop the probability estimation model for intraabdominal abscess. Internal validation using a bootstrap approach was employed to correct for bias, and the model was then validated using an independent dataset comprising of patients who underwent gastrectomy between January 2008 and March 2010. Discrimination and calibration abilities were checked in both datasets. Results: The incidence of intraabdominal abscess in the development set was 7.80% (122/1,564). The surgical approach, operating time, pathologic N classification, body temperature, white blood cell count, C-reactive protein level, glucose level, and change in the hemoglobin level were significant predictors of intraabdominal abscess in the multivariate analysis. The probability estimation model that was developed on the basis of these results showed good discrimination and calibration abilities (concordance index=0.828, Hosmer-Lemeshow chi-statistic P=0.274). Finally, we combined both datasets to produce a nomogram that estimates the probability of intraabdominal abscess. Conclusions: This nomogram can be useful for identifying patients at a high risk of intraabdominal abscess. Patients at a high risk may benefit from further evaluation or treatment before discharge.