• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.1
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• pp.79-89
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• 2005

Objectives : To acquire an improved understanding of oppositional defiant disorder, we evaluated the characteristics of children who have the symptoms of ODD in community sample. Methods : 1200 children from an elementary school in Bucheon (an urban community near Seoul) were recruited by randomized sampling method. By Disruptive Behavior Disorder Scale according to DSM-III-R & DSM-IV, we evaluated the symptoms of ODD and selected subjects with ODD. Psychiatric comorbidity, character trait were compared in subjects with ODD and comparison group. Also we examined the association between prenatal/perinatal risk factors, family functions and the symptoms of ODD. Data were analyzed by appropriate statistical method using SPSS 11.5 window version. Result : Children with oppositional defiant disorder were revealed to have significantly higher rates of psychiatric comorbidity and significantly greater family dysfunction compared to comparison group. Among the prenatal/perinatal risk factors, severe emotional stress during pregnancy, postpartum depression, medication during pregnancy were revealed as risk factors of ODD. In character inventory, ODD group were evaluated to have high score in novelty seeking, harm avoidance, but low in reward dependency. Conclusion : These results support that 1) prenatal/perinatal and psycho-social risk factors could be a important role in the progression of ODD, and 2) children with ODD have diverse comorbid psychiatric symptoms.

• Journal of Intelligence and Information Systems
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• v.23 no.2
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• pp.19-38
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• 2017

Collaborative filtering (CF) algorithm has been popularly used for implementing recommender systems. Until now, there have been many prior studies to improve the accuracy of CF. Among them, some recent studies adopt 'hybrid recommendation approach', which enhances the performance of conventional CF by using additional information. In this research, we propose a new hybrid recommender system which fuses CF and the results from the social network analysis on trust and distrust relationship networks among users to enhance prediction accuracy. The proposed algorithm of our study is based on memory-based CF. But, when calculating the similarity between users in CF, our proposed algorithm considers not only the correlation of the users' numeric rating patterns, but also the users' in-degree centrality values derived from trust and distrust relationship networks. In specific, it is designed to amplify the similarity between a target user and his or her neighbor when the neighbor has higher in-degree centrality in the trust relationship network. Also, it attenuates the similarity between a target user and his or her neighbor when the neighbor has higher in-degree centrality in the distrust relationship network. Our proposed algorithm considers four (4) types of user relationships - direct trust, indirect trust, direct distrust, and indirect distrust - in total. And, it uses four adjusting coefficients, which adjusts the level of amplification / attenuation for in-degree centrality values derived from direct / indirect trust and distrust relationship networks. To determine optimal adjusting coefficients, genetic algorithms (GA) has been adopted. Under this background, we named our proposed algorithm as SNACF-GA (Social Network Analysis - based CF using GA). To validate the performance of the SNACF-GA, we used a real-world data set which is called 'Extended Epinions dataset' provided by 'trustlet.org'. It is the data set contains user responses (rating scores and reviews) after purchasing specific items (e.g. car, movie, music, book) as well as trust / distrust relationship information indicating whom to trust or distrust between users. The experimental system was basically developed using Microsoft Visual Basic for Applications (VBA), but we also used UCINET 6 for calculating the in-degree centrality of trust / distrust relationship networks. In addition, we used Palisade Software's Evolver, which is a commercial software implements genetic algorithm. To examine the effectiveness of our proposed system more precisely, we adopted two comparison models. The first comparison model is conventional CF. It only uses users' explicit numeric ratings when calculating the similarities between users. That is, it does not consider trust / distrust relationship between users at all. The second comparison model is SNACF (Social Network Analysis - based CF). SNACF differs from the proposed algorithm SNACF-GA in that it considers only direct trust / distrust relationships. It also does not use GA optimization. The performances of the proposed algorithm and comparison models were evaluated by using average MAE (mean absolute error). Experimental result showed that the optimal adjusting coefficients for direct trust, indirect trust, direct distrust, indirect distrust were 0, 1.4287, 1.5, 0.4615 each. This implies that distrust relationships between users are more important than trust ones in recommender systems. From the perspective of recommendation accuracy, SNACF-GA (Avg. MAE = 0.111943), the proposed algorithm which reflects both direct and indirect trust / distrust relationships information, was found to greatly outperform a conventional CF (Avg. MAE = 0.112638). Also, the algorithm showed better recommendation accuracy than the SNACF (Avg. MAE = 0.112209). To confirm whether these differences are statistically significant or not, we applied paired samples t-test. The results from the paired samples t-test presented that the difference between SNACF-GA and conventional CF was statistical significant at the 1% significance level, and the difference between SNACF-GA and SNACF was statistical significant at the 5%. Our study found that the trust/distrust relationship can be important information for improving performance of recommendation algorithms. Especially, distrust relationship information was found to have a greater impact on the performance improvement of CF. This implies that we need to have more attention on distrust (negative) relationships rather than trust (positive) ones when tracking and managing social relationships between users.

• Journal of Environmental Impact Assessment
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• v.26 no.4
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• pp.272-289
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• 2017

This study analyzed the status of the naturalized plants in islands in Jeollanamdo from an island biogeographic perspective. As a result of a floristic analysis at 47 inhabited islands and 194 uninhabited islands, 30 families and 134 species naturalized plants are reported. The most commonly occurring naturalized plant from 141 islands was Rumex crispus. The average number of naturalized plants by islands is 20.6 species (${\pm}14.22$) at the inhabited islands and 3.7 species (${\pm}3.89$) at the uninhabited islands. Presence of fifty nine naturalized species at Geumodo in Yeosu-si is the largest in number. The naturalization ratio, which is the ratio of naturalized plants to native plants, is 7.66% (${\pm}3.96$) in the inhabitable islands and 4.97% (${\pm}3.70$) in the uninhabitable islands. The naturalization ratio among islands of the West Sea in Jeollanam-do is 5.92% (${\pm}4.49$), and it is higher than 4.96% (${\pm}2.15$) in islands in the South Sea. Especially, the naturalization ratio at the inhabitable islands, i.e., 8.39% (${\pm}4.37$) at the islands of the West Sea is higher than 5.80% (${\pm}1.41$) at islands in the South Sea. The naturalization ratio of naturalized plants at the islands shows positive correlation with the size of the island (r=0.412, p<0.01), but the correlations with distance from the mainland and altitude above sea level are not significant. Eight ecosystem disturbing species designated by law are reported, and each species shows distinct distributional ranges. The regional differences in the number of naturalized plant species seem to be a result of the complex reflection of natural and human environmental factors, such as the degree of traffic between mainland and islands, degree of cultivation activities, along with the physical environmental differences. Since islands have limited habitats and resources, islands could be more vulnerable to the incoming species from outside, and environmental changes than mainland. Therefore, continuous monitoring and management against the naturalized plants in islands are needed.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.13-22
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• 1977

The following results were obtained in this work intended for getting more informations on features of phosphorus in Korean characteristic virgin, upland and paddy soils for knowing the ways how to evaluate the soil phosphorus availability and utilize fertilizers efficiently. 1. A large part of soil phosphorus is occupied by inorganic phosphorus in the soils of which the cultivated soils showed higher accumulation of applied phosphorus as inorganic forms than the uncultivated soils. The accumulation of organic phosphorus was indicated the highest in the paddy soils, and the lowest in the uncultivated soils. Than the cultuivated soil, the uncultivated soils have higher C/P ratio which was estimated to be related to soil fertility status essentially. 2. Iron phosphate was shown to be the most dominant form in soil phosphorus. Difference in parent rocks, from which the soils were originated, was shown to affect the carious distribution of phosphorus forms in the uncultivated soils to a large extent. The paddy soils have almost same distribution pattern of soil phosphorus forms regardless of different parent rocks. 3. The different methods for available phosphorus estimation extracted different amounts of phosphorus from the soils. Close relations between the available phosphours extracted with the different methods and the amounts of seil inorganic phosphorus were shown : e.g. between Fe-P and available-P by Olsen method. 4. Phosphorus absorption coefficient correlated negatively to soil inorganic phosphorus, and also to available phosphorus extracted with the several methods.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.141-145
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• 2018

BACKGROUND: Agricultural soils are vulnerable from contamination of heavy metal derived from industrial waste. Monitoring on heavy metals on agricultural soils around industrial complexes and evaluation on distributional state on the concentrations of heavy metals in soil have been carried out for problem assessment on soil condition. METHODS AND RESULTS: Soil samples of 1,200, were collected from sixty site of industrial complexes located Gyounggi, Chungbuk, Cheonbuk, and Gyoungnam provinces. Total concentration of Cu, Pb, Zn, Ni, and As were analyzed. Heavy metal concentrations in most soil samples were below warning criteria, except 1 site of Pb, Ni, and As, separately. The comparison of mean values of heavy metal concentrations between soils around industrial complexes and paddy soils, showed similar levels of heavy metals, except Pb. The concentrations of lots of heavy metals were distributed between from warning criteria to one fifth level of warning criteria. However, in the case of Cu and Pb, more than 30% were distributed below one twenties level of warning criteria. These results were very similar with the distribution state of heavy metals in upland soils. The concentrations of heavy metals in surface soil and subsoil were similar among the heavy metals in soils around industrial complexes. CONCLUSION: The concentrations of heavy metals in soils around industrial complexes were distributed close to warning criteria. Long term and continous monitoring and evaluation on heavy metals in agricultural soils are required for food safety and sustainable soil management.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.2
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• pp.78-88
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• 2015

In the 1920s, the period of cultural governance ruled by Japan, the diverse media were founded and various events were conducted to boost circulation. Under the Japanese colonial period in 1920s, a number of media - newspapers and magazines - were published and often they carried out entertaining events in order to obtain more subscribers. A hobby magazine, Samchunri, for instace, set up a media event to selecting Korea's eight beautiful scenary (Bandopalgyong) for the first edition in 1929. The paper aims to analyse and understand the perception of landscape in 1929 through the media event carried out by Samchunri. In particular, the selection was made by well-known writers within Japanese colonial period 1910 - 1945). The selection process and views from the writers on landscape were analysed; firstly, the selection of Bandopalgyong was carried out by questionnaires to writers in 1929 where Korea is under Japanese colonial rules. The conditions of the selection were unknown; however, the purpose was enlightening the people specially the youngs and introduction of beautiful places in Korea. As a result, views and opinions on Bandopalgyong by the writers were progressed. Secondly, within the Bandopalgyong, the natural landscape areas include Gumgansan(金剛山), Daedonggang(大洞江), Buyeo(扶餘), Gyongju(慶州), Myongsasipri (明沙十里), Haundae(海雲臺), Baekdusan(白頭山), and Choksukru(矗石樓). Those chosen places were not cohesive nor did not have any consistant reasons to be chosen in terms of size and location; however, some writers claimed that there were other places to match the chosen ones and therefore, the selection process was highly dependent on access (i.e. transport). Thirdly, the travelogue on Baekdusan and Nackwhaam(洛花岩) illustrated interesting views on landscape in particular. Baekdusan landscape were described in overlaping with long history and national soul. In the Nackwhaam travelogue, it described 'Buyeo (夫餘) was an ancient capital of Backjae Dynasty and empty place' as well as denying Chosun Dynasty. It was assumed that the two places weren't visited but rewritten with existing literatures. Fourthly, edited by Kim Dong Whan, a travelogue style book, 'Bandosanha' was published in 1941. It did repeat the selection of Bandopalgyong, but this time, it was classified the eight beautiful landscape into two categories; historic/cultural places and natural landscape. This paper was able to analyse and understand the perception of landscape in 1929 through the travelogue of Samchunri. It is an empirical study on the process and perception on Korea landscape under Japanese colonical period by views of the selected writers.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.353-360
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• 2005

The aim of this study was to investigate the impact of depression, somatization, and jaw disability on graded chronic pain of TMD using Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Ninety-three patients (17 men and 76 women, mean$\pm$SD age of 30.1$\pm$12.5 years) diagnosed with TMD based on RDC/TMD axis I criteria were administered RDC/TMD axis II history questionnaire. The relationships between depression, somatization, jaw disability, and each parameters of graded chronic pain (e.g. pain intensity, pain days, disability score, disability days, graded chronic pain scale) were analyzed by multiple regression analysis. The obtained results were as follows: 1. Among 93 TMD patients, the prevalence of low disability group of graded chronic pain scale was 42.0% and high disability group of graded chronic pain scale was 51.5%. 2. Depression did not show any significant influences on pain intensity, pain days, disability score, disability days, and graded chronic pain scale. 3. Somatization showed a significant effect on pain intensity (p<0.01), disability days (p<0.01), and graded chronic pain scale (p<0.01) except for both pain days and disability score. 4. Jaw disability also showed a significant effect on pain intensity (P<0.001), disability days (p<0.01), and graded chronic pain scale (P<0.001) except for both pain days and disability score. Somatization and jaw disability may closely relate to the pain intensity and degree of disability that TMD patients perceive. Therefore, comprehensive understanding of psychological profile and improvement of functional limitation of jaw movements in the patient should be considered to obtain an excellent outcome of chronic TMD management.

• Korean Journal of Psychosomatic Medicine
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• v.16 no.1
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• pp.38-46
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• 2008

Objectives : The purpose of this study is to investigate the minor stress in daily life related to undergoing hemodialysis and the relationship between minor stresses, coping skills, and subjective quality of life among the patients with end stage renal disease. Methods : Seventy seven patients on hemodialysis were enrolled in this study. Minor stress was assessed with daily stress inventory-Korean version(K-DSI), ways of coping checklist identified the use of the following coping strategies:problem-focused, seek social support, emotion-focused coping and wishful thinking. Socio-demographic data were obtained and World Health Organization-Quality of Life Scale(brief form) was also administered to subjects. Results : Participants mean age was $55.92{\pm}13.71$ years. The mean of the event, impact and impact/event (I/E) ratio scores of K-DSI were $29.06{\pm}21.57$, $88.69{\pm}75.88$ and $2.92{\pm}1.11$, respectively. These scores were much higher than normative data of K-DSI. Among the 5 categories of this inventory, the scores of cognitive stressors were highest. 5 categories of the inventory showed positive relationship with way of coping subscales, which showed coefficient of correlation between 0.259(p<.01) and 0.495(p<.001). However, no significant correlation was found between minor stress subscales and quality of life. Hemodialysis patients in our study used more emotional-focused coping methods, which was considered as passive way of cope than problem-orientated coping methods. Conclusion : The main findings of this study indicated that patients on hemodialysis showed higher level of perceived minor stress than normal population. The patients treated with hemodialysis tend to use passive way of coping primarily. For assessing the stress in patients on hemodialysis, clinician has to consider both level of perceived minor stress and the ways of coping the patients primarily use.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.25-36
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• 2005

Several metalliferous and coal mines, including Myungjin, Seojin and Okdong located at the upper watershed of Okdong stream, were abandoned or closed since 1988 due to the mining industry promotion policy. Thus these disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. Acid mine drainage (AMD) and waste water effluents from the closed coal mines were very strongly acidic showing pH ranges of 2.7 to 4.5 and had a high level of Total Dissolved Solids (TDS) showing the ranges of 1,030 to 1,947 mg/L. Also heavy metal concentrations in these samples such as Fe, Cu, Cd and anion such as sulfate were very high. Concentrations of water soluble heavy metals in the Okdong streams were in the orders of Fe>Al>Mn>Zn>Cu>Pb>Cd, indicating Fe from the AMD and waste water effluents contributed greatly to the quality of water and soil in the lower watershed of Okdong stream. Copper concentrations in the effluents from the tile drainage of mine tailings dams were highest during the raining season. Water Pollution Index (WPI) of the surface water at the upper stream of Okdong river where AMD of the abandoned coal mines was flowed into main stream were in the ranges of 16.3 to 47.1. On the other hand, those at the mid stream where effluents from tailings dams and coal mines flowed into main stream were in the WPI ranges of 10.6 to 19.5. However, those at the lower stream were ranged from 10.6 to 14.9. These results indicated that mining wastes such as AMD and effluents from the closed mines were the major source to water pollution at the Okdong stream areas.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.1
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• pp.13-18
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• 2009

Accurate solar radiation data are critical to evaluate major physiological responses of plants. For most upland crops and orchard plants growing in complex terrain, however, it is not easy for farmers or agronomists to access solar irradiance data. Here we suggest a simple method using a sun-slope geometry based topographical coefficient to estimate daily solar irradiance on any sloping surfaces from global solar radiation measured at a nearby weather station. An hourly solar irradiance ratio ($W_i$) between sloping and horizontal surface is defined as multiplication of the relative solar intensity($k_i$) and the slope irradiance ratio($r_i$) at an hourly interval. The $k_i$ is the ratio of hourly solar radiation to the 24 hour cumulative radiation on a horizontal surface under clear sky conditions. The $r_i$ is the ratio of clear sky radiation on a given slope to that on a horizontal reference. Daily coefficient for slope correction is simply the sum of $W_i$ on each date. We calculated daily solar irradiance at 8 side slope locations circumventing a cone-shaped parasitic volcano(c.a., 570m diameter for the bottom circle and 90m bottom-to-top height) by multiplying these coefficients to the global solar radiation measured horizontally. Comparison with the measured slope irradiance from April 2007 to March 2008 resulted in the root mean square error(RMSE) of $1.61MJ\;m^{-2}$ for the whole period but the RMSE for April to October(i.e., major cropping season in Korea) was much lower and satisfied the 5% error tolerance for radiation measurement. The RMSE was smallest in October regardless of slope aspect, and the aspect dependent variation of RMSE was greatest in November. Annual variation in RMSE was greatest on north and south facing slopes, followed by southwest, southeast, and northwest slopes in decreasing order. Once the coefficients are prepared, global solar radiation data from nearby stations can be easily converted to the solar irradiance map at landscape scales with the operational reliability in cropping season.