• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.824-829
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• 2011

In recent years, there has been an increasing public concern about fecal contamination of water, air and agricultural produce by pathogens residing in organic fertilizers such as manure, compost and agricultural by-products. Efforts are now being made to control or eliminate the pathogen populations at on-farm level. Development of efficient on-farm strategies to mitigate the potential risk posed by the pathogens requires data about how the pathogens prevail in livestock manure composts and organic fertilizers. Microbiological analysis of livestock manure composts and organic fertilizers obtained from 32 and 28 companies, respectively, were conducted to determine the total aerobic bacteria count, coliforms, Escherichia coli count and the prevalence of Staphylococcus aureus, Bacillus cereus, Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes, and Cronobacter sakazakii. The total aerobic bacteria counts in the livestock manure composts and organic fertilizers were in the range of 7 to $9log\;CFU\;g^{-1}$ and 4 to $6log\;CFU\;g^{-1}$, respectively. In the livestock manure composts, coliforms and E. coli were detected in samples obtained from 4 and 2 companies, respectively, in the range of 2 to $5log\;CFU\;g^{-1}$ and $2log\;CFU\;g^{-1}$. In the organic fertilizers, coliforms and E. coli were detected in samples obtained from 4 and 1 companies, respectively, in the range of 1 to $3log\;CFU\;g^{-1}$ and $2log\;CFU\;g^{-1}$. In 3 out 32 compost samples, B. cereus was detected, while other pathogens were not detected. In 28 organic fertilizers, no pathogens were detected. The complete composting process can result in the elimination of pathogens in livestock manure compost and organic fertilizer. The results of this study could help to formulate microbiological guidelines for the use of compost in environmental-friendly agriculture. This research provides information regarding microbiological quality of livestock manure compost and organic fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.789-792
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• 2010

Major impacts of climate change expert that soil erosion rate may increase during the $21^{st}$ century. This study was conducted to assess the potential impacts of climate change on soil erosion by water in Korea. The soil loss was estimated for regions with the potential risk of soil erosion on a national scale. For computation, Universal Soil Loss Equation (USLE) with rainfall and runoff erosivity factors (R), cover management factors (C), support practice factors (P) and revised USLE with soil erodibility factors (K) and topographic factors (LS) were used. RUSLE, the revised version of USLE, was modified for Korean conditions and re-evaluate to estimate the national-scale of soil loss based on the digital soil maps for Korea. The change of precipitation for 2010 to 2090s were predicted under A1B scenarios made by National Institute of Meteorological Research in Korea. Future soil loss was predicted based on a change of R factor. As results, the predicted precipitations were increased by 6.7% for 2010 to 2030s, 9.5% for 2040 to 2060s and 190% for 2070 to 2090s, respectively. The total soil loss from uplands in 2005 was estimated approximately $28{\times}10^6$ ton. Total soil losses were estimated as $31{\times}10^6$ ton in 2010 to 2030s, $31{\times}10^6$ ton in 2040 to 2060s and $33{\times}10^6$ ton in 2070 to 2090s, respectively. As precipitation increased by 17% in the end of $21^{st}$ century, the total soil loss was increased by 12.9%. Overall, these results emphasize the significance of precipitation. However, it should be noted that when precipitation becomes insignificant, the results may turn out to be complex due to the large interaction among plant biomass, runoff and erosion. This may cause increase or decrease the overall erosion.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.191-199
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• 2016

Objectives : Despite the increased popularity of highly caffeinated beverages, there is little research examining psychiatric adverse effects. The purpose of this study was to investigate the relationships among pattern of highly caffeinated beverage intake and depressive symptom, suicidal ideation, suicidal plan, suicidal attempt in Korean adolescents. Methods : The data was obtained from the 2014 Korean Youth's Risk Behavior Web-based Study by Korea Centers for Disease Control & Prevention. All participants conducted web-based questionnaire survey. Chisquare test and multiple logistic regression analysis were performed to determine the association among highly caffeinated beverage intake pattern, depressive symptom, suicidal ideation, suicidal plan and suicidal attempt adjusting for differences in age, gender, academic achievement, socioeconomic status. Results : A total of 71,638 participants were enrolled in this study. Depressive symptom, suicidal ideation, suicidal plan and suicidal attempt were significantly more frequent in the group with presence of highly caffeinated beverage intake within 1 week than in non-drinker group(p<0.01). Highly caffeinated beverage intake was significantly associated with suicidal attempt(OR=1.99 ; 95% CI, 1.77-2.22). In addition, depressive symptom, suicidal ideation, suicidal plan and suicidal attempt were significantly more common in the group with heavy-drinker who exceed recommended daily intake dose of caffeine than in the group with light-drinker(p<0.01). Heavy drinking of caffeinated beverage was significantly associated with suicidal attempt(OR=4.05 ; 95% CI, 3.02-5.43). Conclusions : We found that highly caffeinated beverage intake was related to more frequent depressive symptom, suicidal ideation, plan, attempt in adolescents. Also, caffeine intake which exceed recommended daily intake dose identified the predictor of suicidal attempt. Our result suggested that clinicians need to be aware of the possible psychiatric adverse effects of highly caffeinated beverage in vulnerable population including young adolescents.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.66-73
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• 2016

Objectives : The purpose of this study was to investigate the characteristics of psychosocial factors related to functional dyspepsia(FD) and their effects on quality of life(QOL) in firefighters. Methods : This study examined data collected from 1,217 firefighters. We measured psychological symptoms by Patient Health Questionnaire-9(PHQ-9), Generalized Anxiety Disorder questionnaire(GAD-7), Korean Occupational Stress Scale(KOSS), Ways of Coping checklist(WCCL), Rosenberg's Self-Esteem Scale(RSES) and World Health Organization Quality of Life Scale abbreviated version(WHOQOL-BREF). Chi-square test, independent t-test, Pearson's correlation test, logistic regression analysis, and hierarchical regression analysis were used as statistical analysis methods. Results : For the group with FD, the male participants showed significantly higher frequency(p=0.006) compared to the female participants. The group with FD had higher scores for depressive symptoms(p<.001), anxiety (p<.001), and occupational stress(p<.001), and did lower scores for self-esteem(p=.008), quality of life(p<.001) than those without FD. The FD risk was higher in the following KOSS subcategories: job demand(OR 1.94, 95% CI : 1.29-2.93), lack of reward(OR 2.47, 95% CI : 1.61-3.81), and occupational climate(OR 1.51, 95% CI : 1.01-2.24). In the hierarchical regression analysis, QOL was best predicted by depressive symptoms, self-esteem, and occupational stress. Three predictive variables above accounts for 42.0% variance explained of total variance. Conclusions : The psychosocial factors showed significant effects on FD, and predictive variables for QOL were identified based on regression analysis. The results suggest that the psychiatric approach should be accompanied with medical approach in future FD assessment.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.195-209
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• 2021

According to the 2019-2020 social media usage survey conducted by the Seoul e-commerce center, 5 out of 10 consumers have experienced shopping through social media. The cost of traditional advertising media has been reduced and advertising spending on social media has risen by 74%, indicating that social media is becoming a more important marketing element. While the number of users of social media has increased and corporate marketing activities have increased accordingly, research has been conducted in various aspects of marketing such as user motivation for social media, satisfaction, and purchase intention. There was no subdivided study on the differences in the social media usage frequency of consumers in actual purchasing behavior. This study attempted to identify differences in consumer characteristics by cluster in the agrifood purchase situation by grouping them by type according to the frequency of use of social media for consumers who purchase agri-food online. Product involvement, product need, and online purchase channel Consumer characteristics such as demographic distribution, perceived risk, and eating and lifestyle in each cluster were checked for the three agrifood purchase situations including choice, and types for each cluster were presented. To this end, questionnaire data on the frequency of social media use and online agrifood purchase behavior were collected from 245 consumers, and the validity of the measurement variables was secured through factor analysis and reliability analysis. As a result of cluster analysis according to the frequency of social media use, it was divided into three clusters. The first cluster was a group that mainly used open social media, and the second cluster was a group that used both open and closed social media and online shopping malls; The third cluster was a group with low online media usage overall, and the characteristics of each cluster appeared. Through regression analysis, the effect on product involvement, product need, and purchase channel selection when purchasing agri-food online through each of the three clusters was confirmed through regression analysis. As a result of the regression analysis, the characteristic of cluster 1 in the situation of purchasing agri-food online is a male in his 30s living in a rural area who has no reluctance to purchase agri-food on social media or online shopping malls. The characteristics of cluster 2 are mainly consumers who are interested in purchasing health food, and the consumer characteristics are represented. In the case of cluster 3, when purchasing products online, they purchase after considering quality and price a lot, and the consumer characteristics are represented as people who are more confident in purchasing offline than online. Through this study, it is judged that by identifying the differences in consumer characteristics that appear in the agri-food purchase situation according to the frequency of social media use, it can be helpful in strategic judgments in marketing practice on social media customer targeting and customer segmentation.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.167-178
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• 2021

The purpose of this study is to analyze the direct investment decision factors in the Kaesong Industrial Complex and Vietnam, and to contribute to the creation of domestic jobs and the revitalization of the inter-Korean economy. According to the analysis, most of the Kaesong Industrial Complex and Vietnamese investment companies are entering the complex for the purpose of utilizing cheap labor, cheap factory locations, sales/development of local markets, and bypass export production bases in third countries. This can be divided into production-efficient investors using differences in production price such as labor costs and market-oriented investors to sell and expand the local market, which seems to be consistent with global direct investment patterns such as Nike, Apple, and Amazon. However, even if the North Korea-U.S. denuclearization talks ease or lift sanctions, Vietnamese investors' willingness to invest in the North Korea has been most burdened by the possibility of closing special economic zones due to political risks. Last but not least, it is important to note that those willing to invest in North Korea are mostly smaller enterprises in textiles, sewing, footwear and leather industries-those that benefit from low-cost labor. Since their size is small, they need policy support in financing, especially in the early stages of their business. Even after they grow past the early stages, those without collateral would still need state guarantee letters to get financing. Thus, it is worth considering to use the Inter-Korean Cooperation Fund to compensate commercial banks for bad loan loss or for low-interest loans for smaller SMEs. The interviews with SMEs found that red-tape is one of the biggest difficulties they face. Thus, it is recommended that a one-stop service agency should be established to cover all processes and issues related to inter-Korean economic cooperation to eliminate redundancy and expediate government support for SMEs.

• Journal of Internet Computing and Services
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• v.22 no.1
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• pp.41-50
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• 2021

Cyber Kill Chain is derived from Kill chain of traditional military terms. Kill chain means "a continuous and cyclical process from detection to destruction of military targets requiring destruction, or dividing it into several distinct actions." The kill chain has evolved the existing operational procedures to effectively deal with time-limited emergency targets that require immediate response due to changes in location and increased risk, such as nuclear weapons and missiles. It began with the military concept of incapacitating the attacker's intended purpose by preventing it from functioning at any one stage of the process of reaching it. Thus the basic concept of the cyber kill chain is that the attack performed by a cyber attacker consists of each stage, and the cyber attacker can achieve the attack goal only when each stage is successfully performed, and from a defense point of view, each stage is detailed. It is believed that if a response procedure is prepared and responded, the chain of attacks is broken, and the attack of the attacker can be neutralized or delayed. Also, from the point of view of an attack, if a specific response procedure is prepared at each stage, the chain of attacks can be successful and the target of the attack can be neutralized. The cyber command and control system is a system that is applied to both defense and attack, and should present defensive countermeasures and offensive countermeasures to neutralize the enemy's kill chain during defense, and each step-by-step procedure to neutralize the enemy when attacking. Therefore, thist paper proposed a cyber kill chain model from the perspective of defense and attack of the cyber command and control system, and also researched and presented the threat classification/analysis/prediction framework of the cyber command and control system from the defense aspect

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1819-1827
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• 2021

Land-use/cover change caused by rapid urbanization in South Korea is one of the concerns in flood risk management because groundwater recharge by precipitation hardly occurs due to an increase in impermeable surfaces in urban areas. This study investigated the hydrologic effects of land-use/cover on groundwater recharge in the Yeonje-gu district of Busan, South Korea. A statistical time series analysis was conducted with temporal variations of precipitation and groundwater level to estimate lag-time based on correlation coefficients calculated from auto-correlation function (ACF), cross-correlation function (CCF), and moving average (MA) at five sites. Landform and land-use/cover within 250 m radius of the monitoring wells(GW01, GW02, GW03, GW04, and GW05) at five sites were identified by land cover and digital map using Arc-GIS software. Long lag-times (CCF: 42-71 days and MA: 148-161 days) were calculated at the sites covered by mainly impermeable surfaces(GW01, GW03, and GW05) while short lag-times(CCF: 4 days and MA: 67 days) were calculated at GW04 consisting of mainly permeable surfaces. The results suggest that lag-time would be one of the good indicators to evaluate the effects of land-use/cover on estimating groundwater recharge. The results of this study also provide guidance on the application of statistical time series analysis to environmentally important issues on creating an urban green space for natural groundwater recharge from precipitation in the city and developing a management plan for hydrological disaster prevention.

• 한국노년학
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• v.38 no.4
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• pp.891-903
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• 2018

This study investigated the relation between frailty, social support, and health-related quality of life to provide basic data to improve the health-related quality of life of old-old elderly who are a high risk group for frailty. For this descriptive study, one-on-one interviews with structured questionnaires were conducted for elderly aged 75 years or older at elderly welfare facilities in K county from March 01 to 31 in 2016, and a total of 211 elderly were interviewed. The collected data were analyzed by t-test, Pearson's correlation coefficient, and path analysis using SPSS/WIN and AMOS 18.0 program. For the differences between the age groups, those aged over 80 years had a significantly higher frailty (t=-2.51, p=.013) and a lower health-related quality of life than those aged below 80 years (t=3.29, p=.001); however, there was no significant difference in social support (t=1.28, p=.201). The correlation between frailty, social support and health-related quality of life showed that as frailty became higher, social support (r=-.21, p=.003) and health-related quality of life (r=-.65, p<.001) were significantly lower, and health-related quality of life was significantly higher with a higher social support (r=.18, p=.010). As a result of investigating the mediating effects of frailty between social support and health-related quality of life, social support had a significant direct effect on frailty (${\beta}=-.21$, p=.016) and frailty had a significant direct effect on health-related quality of life (${\beta}=-.06$, p=.004); however, social support had no significant direct effect on health-related quality of life (${\beta}=.00$, p=.562). Social support had a significant indirect effect on health-related quality of life and a mediating effect on frailty (${\beta}=.01$, p=.012); therefore, the full mediation effect of frailty between social support and health-related quality of life was verified. Social support prevents frailty, and improving frailty enhances health-related quality of life. Therefore, it is necessary to develop a multifactorial frailty prevention program that includes age-specific social support strategies to improve the health-related quality of life in old-old elderly.

• International Area Studies Review
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• v.22 no.2
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• pp.163-186
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• 2018

The purpose of this study is to analyze the institutional conditions and problems for the transition to the North Korean economic system. As a research method, we first analyzed the legislative processes of 4th stage market reform policies (liberalization, privatization, privatization, and corporation) by major economic transition countries. And we found out the difference with North Korea. Based on this, it analyzed the process of institutionalization of North Korea's 4th stage economic reform policies (7.1 measures, comprehensive market policies, Currency reform, 6.28 policy). According to research, There are three important conditions that can not compare the changes of the North Korean market economy with those of the transition economies. First, the internal and external conditions and environment for the transition of the economic system and the role of the state and civil society are very different. Second, the means and objectives of the policy decision process and the implementation process are different. Third, it differs absolutely in terms of the nature and effectiveness of the nation's political and economic policies. Fourth, the priority, contents, and legislation process of economic policies for economic reform differ considerably from those of North Korea. Especially, when discussing the possibility of transition to the 'Chinese model', it is accompanied a considerable risk. It is because the purpose of market entry of control power in North Korea and their survival network are quite unique. In addition, China's domestic market size, population size, and type of control are quite different from North Korea. A necessary and sufficient condition for the transition of the North Korean economic system is the relaxation of physical control mechanisms and institutions in the market area. Next, it is necessary to make a legitimate institutionalization as well as an entire survey on the illegal ownership market. Based on this, it is necessary to gradually change the dependence of the domestic market on China to South Korea. In other words, this is a paradigm shift in the semi-controlled power exclusion, post-automation and domestic market.