• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7719-7724
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• 2014

Background: Lymph node metastasis is believed to be a dependent negative prognostic factor of esophageal cancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distant lymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT and contrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophageal cancer. Materials and Methods: One hundred and fifteen cases were examined with enhanced 64-slice-MSCT scan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. The primary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed within one week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the gold standard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCT was conducted. Results: There were 946 lymph node groups resected during surgery from 115 patients, and 221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT in detecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and 89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05). The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, as compared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with or without metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distant lymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity of FDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). Conclusions: FDG PET/CT is more sensitive than MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophageal cancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detecting both regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value in distinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CT with MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.4
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• pp.11-16
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• 2015

Spatial and temporal information on near-surface air temperature is important for understanding global warming and climate change. In this study, the estimation algorithm of near-surface air temperature in Korea was developed by using spatial homogeneous surface information obtained from satellite remote sensing observations. Based on LST(Land Surface Temperature), NDWI(Normalized Difference Water Index) and NDVI(Normalized Difference Vegetation Index) as independent variables, the multiple regression model was proposed for the estimation of near-surface air temperature. The different regression constants and coefficients for warm and cold seasons were calculated for considering regional climate change in Korea. The near-surface air temperature values estimated from the multiple regression algorithm showed reasonable performance for both warm and cold seasons with respect to observed values (approximately $3^{\circ}C$ root mean-square error and nearly zero mean bias). Thus;the proposed algorithm using remotely sensed surface observations and the approach based on the classified warm and cold seasons may be useful for assessment of regional climate temperature in Korea.

• Journal of the Korean Regional Science Association
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• v.12 no.2
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• pp.21-36
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• 1996

This thesis focused on the extent of the area-by-area gap of the unit production cost that should be taken into account without exception in supply of the local public goods production cost. With the advent of the local autonomy era, what should be considered in the local governmen's production of the local public goods are the government's fiscal capacity and the environmental difference that shows up in accordance with the area's characteristics. Though with the same level of the fiscal capacity, an occurrence of environmental difference will lead inevitably to the different level of actual supply of the local public goods. The method of analysis used in this thesis was first to bring out implicit price, to combine this with induced expenditure function, to separate demand function parameter and cost function parameter, and then to analyzed the impact of environmental variables on the production cost. The environmental variables were set on the basis of the ones that affected expenditure per person of the public goods. The analysis was conducted in distinction of city areas and county areas. The results showed that, in cases of cities, more production cost of the public goods was in presence in urban areas and in areas where there was sluggish development. In other words, distinction could be drawn between areas where there was a large consumption of production cost resulting from poor environmental sparked by slow development and those where additional costs were required due to population concentration caused by a certain level of accomplished development. In the meantime, in cases of county areas, the results were around the same. However, a comparison between city areas and county ones told that overall difference between city areas was not that big in the production cost while that in county areas was large enough. In times ahead, in implementation of grant-in-aid scheme, production cost index for local public goods could be used as it was written in consideration of environmental characteristics of areas concerned.

• Korean Journal of Head & Neck Oncology
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• v.14 no.2
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• pp.191-198
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• 1998

Objectives: We performed an immunohistochemical study to examine the place of neovascularization in the tumorigenic process of follicular thyroid carcinoma and to determine whether tumor angiogenic activity in follicular carcinoma plays a role in tumor aggression. Materials & Methods: We studied 63 follicular thyroid carcinomas and compared with 22 follicular adenomas. The areas of capsular invasion, vascular invasion and cellular atypism of the tumor were confimed on H & E stains. The paraffin embedded tissues were stained by the use of monoclonal antibodies against Ag CD34. Microvesseles were counted in the area of highest vascular density at 200 times magnification. The microvessel densities(MVD) were analized in relation to histologic type and location of the tumors. Results: There were 59 minimal invasive types and 4 widely invasive types of carcinoma. In the histologic specimens of carcinomas, capsular invasion was identified in all the cases, vascular invasion in 46 and cellular atypism in 24. Mean values of the MVDs of the minimal invasive carcinomas, the widely invasive carcinomas and the adenomas were $263.8{\pm}69.2,\;256.l{\pm}49.3\;and\;241.5{\pm}159.4$, respectively and there was no significant difference between each group. In follicular carcinomas, there was a regional difference of the MVDs. The areas of tumor showing cellular atypism and adjacent to or penetrating the capsule, in which represents the tumorigenic process of carcinoma, had a higher rate of vascularization, than other areas of the tumor(p<0.05). However, these features were not noted in the follicular adenomas. Conclusion: Although there was no significant difference of the MVD between follicular carcinomas and adenomas, there was a regional difference of the MVD within the carcinomas and the values were significantly higher in the more malignant areas, as indicated by cellular atypism and capsular invasion. Therefore, tumor angiogenic activity measured by MVD may play a role in tumor aggression in follicular thyroid carcinoma.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.273-279
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• 2022

In a recent decade, university closures have been a critical regional issue as a total of 17 universities have been closed while many more are facing closure in Korea. The local impact of university closures in the regions with declining populations has been far more detrimental and considered as one of the significant factors of the declining local economy, especially in the neighboring residential sectors. This study has taken an empirical approach to investigate the local impact of university closure on the housing market through a case of Dong-Pusan College in Busan, Korea. The study utilized Difference-in-Difference (DiD) to analyze the housing prices in proximity to the university and identified several factors associated with the local decline in the housing market in relation to university closure.

• Asia-Pacific Journal of Business
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• v.14 no.1
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• pp.341-350
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• 2023

Purpose - How are gains from trade distributed between countries when economic integration is achieved through free trade? The purpose of this paper is to answer this question. Design/methodology/approach - This study attempts to address the issue of distribution of trade gains between participating countries following economic integration in terms of positive economics. The analysis is therefore based on a theoretical methodology. Findings - First, commodity prices fall and consumer surplus increases in both large and small countries. Second, when economic integration into free trade is achieved, gains from trade always exist in small countries. However, the size of trade gains depends on the degree of difference from the market size of the partner country, the large country. However, the size of the gains from trade depends on the extent of difference between the market size of the large country. If the market size of a large country is much larger and there is a large difference, trade gains will be very large, whereas if the market size is similar, profits of domestic firm will decrease. Therefore, in that case, the size of the gains from trade becomes relatively small because only the gains from exchange exists. On the other hand, in a large country with a large market size, there is a possibility of trade gains only when the market size is similar to that of a small country, which is a trading partner. However, if there is a large difference in market size, the decrease in profits of domestic firm is relatively larger than the increase in consumer surplus due to trade, and rather, a trade loss occurs. Research implications or Originality - Our analysis contributes to filling the gaps in the literature regarding the distribution of gains from trade, and from a policy point of view, it is meaningful in examining the impact of market size, an important variable considered in regional economic integration of countries.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.81-88
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• 2005

There have been many studies on generation equipment and plant piping, but there is no significant study result on the heat transportation pipe. As such, this study established basic theory on the compensated method among buried pipe for regional heating, and further obtained the following results by applying the conditions of AGFW and NCHPP respectively in calculation of friction and maximum installation distance for the buried pipe. Friction coefficient according to the types and physical properties of soil, friction and maximum installation distance were compared to set the application value of friction coefficient according to the location of works. Calculation formula of clay load to be applied for calculation of friction was introduced to the formula of AGFW and the formula of NCHPP that has been used in Nowon district since 1997 to determine the difference and applicability. $120^{\circ}C$ and $95^{\circ}C$ were applied in temperature difference for expansion volume to compare the arm length at the curve pipe so thai it can be reflected in the design in the future. Maximum installation distance according to thickness of pipe was compared to present the necessity of unified specification so that same kinds of pipe materials can be used for same kinds of works.

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.59-69
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• 1994

Dietary fiber(DF) intakes of Korean during 1969∼1990 were estimated and the major food sources of fiber were analyzed using the data from the Annual Reports of Korean National Nutrition Survey. The estimated daily DF intake of Korean has gradually decreased during the 22 years, from 24.46g in 1969 to 17.31g in 1990 with a remarkable decline in 1987. The average DF intakes of the rural population were higher than those fo urban's until 1980, but the situation was reversed until 1987 and the regional difference in DF consumption disappeared thereafter. Vegetables, cereals, grain and legumes were the major sources of fiber for Korean in recent 5 years(1986∼1990), providing 32%, 16% and 19% of DF intake respectively. Throughout the 22years, the intakes of DF from cereals and fresh vegetables have been reduced and those from processed vegetables, seaweeds and fruits has been increased. Df intake from legumes continuously increased until 1986, and it decreased thereafter. Rural population consumed more fiber from cereals than the urban's during the 1970s, but thereafter regional difference in cereal fiber intakes became insignificant. Urban population consumed more fiber from legumes and fruits than the rural's through the entire period. The results of this study indicate that the present DF intake of Korean is considerably lower than generally anticipated and is below the tentative recommended DF intake and thus higher DF intake than the present level is needed.

• Journal of the Korean Regional Science Association
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• v.13 no.2
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• pp.93-118
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• 1997

Main findings of this study are as follows. Time-space model of Korea for urban growth model is established. The variables of space model resulted in job and education, which both are significant at 0.01 level and positive. The effect of job and education on the urban growth are 0.76 and 0.29 respectively in average. the determinants for deciding the influences for job variable are income variable and price-level variable. Income variable contributes 68.66% and the direction is negative while contribution of price-level variable is 29.90% and the direction is positive. The determinants for education variable are income, unemployment and wage difference between university graduates and high school graduates. The contribution and the high school graduates. The contribution and the direction of each variable for education variable are 63.6% and positive for the unemployment variable, 15.99% and negative for the income variable and 13.75% and positive for the wage difference variable. This study in different from previous works in three ways. The first is to establish the time-space model which could consider the time and space factor simultaneously. The second is to build data bases which contain the data of almost every city and every year in Korea during the objective period, which make the analysis continuous. The third is that the general analytic framework for the study is macrosocial one rather than a behavioral one, which means the unit of analysis is the metropolitan community and each city occupies population actively through it's potential power such as jobs, education and so on rather than a city population is the passive result of migration.

• Journal of the Korean Regional Science Association
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• v.33 no.4
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• pp.19-28
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• 2017

This study has intended to perform comparative analysis of climate change adaptation-related recognition between public officials and citizens in ChungCheongBukDo-Province, Korea. To reach this goal, we identified difference between the two groups by prioritizing target group's adaptation policies for climate change, and analyzing climate change adaptation-related recognition in each sector. Climate change adaptation policies can have great policy utility when the boundaries between policy makers and detainees are blurred. Therefore, this study has suggested some measures to reduce the recognition gaps between the target groups by analyzing the characteristics of the groups.