• Journal of the Korean GEO-environmental Society
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• v.24 no.12
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• pp.61-67
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• 2023

Heat pipes located underground in urban areas and operated under high temperature and pressure conditions can cause large-scale human and economic damage if damaged. In order to predict damage in advance, damage and construction information of heat pipe are analyzed to derive independent variables that have a correlation with frequency of damage, and a simple regression analysis modified model using each variable is applied to the field. However, as the correlation between independent variables applied to the model increases, the independence between variables is harmed and the reliability of the model decreases. In this study, the independence of the pipe diameter, burial depth, insulation level of monitoring system, and disconnection or short circuit of the detection line, which are judged to be interrelated, was tested to derive a method for combining variables and setting categories necessary to apply to the frequency of damage estimation model. For the test of independence, the continuous variables pipe diameter and burial depth were each converted into three categories, insulation level of monitoring system was converted into two categories, and the categorical variable disconnection or short circuit of the detection line status was kept as two categories. As a result of the test of independence, p-value between pipe diameter and burial depth, level of monitoring system and disconnection or short circuit of the detection line was lower than the significance level (α = 0.05), indicating a large correlation between them. Therefore, the pipe diameter and burial depth were combined into one variable, and the categories of the combined variable were set to 9 considering the previously set categories. The insulation level of monitoring system and the disconnection or short circuit of the detection line were also combined into one variable. Since the insulation level is unreliable when the detection line status is disconnection or short circuit, the categories of the combined variable were set to 3.

• Korean Journal of Culture and Social Issue
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• v.9 no.1
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• pp.139-178
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• 2003

This study investigates Koreans respondents' perception of American society, American people and its influence in Korea and the world. These analyses have been conducted to provide the psychological, social and cultural basis for understanding the anti-American sentiments among Korean junior high school students, university students and adults. American influence is further divided into American influence on Korean society, on North-South Korean unification, and in the world. In addition, respondents' knowledge of the USA, their satisfaction with the current political functioning, and background information were obtained. A total of 763 respondents (171 junior high school students, 250 university students, and 342 parents of junior high school students) completed a survey questionnaire developed by the first two authors. The overall results indicate that the respondents had a negative view of the USA and its influence in Korea and the world. Majority of respondents perceive American society as being commercial, exclusionary, and ethnocentric. Some respondents perceive American society as being democratic and advanced. As for American people, they are perceive them as being selfish and at the same time independent and carefree. The trust for American society is very low. As for American influence in Korea, it is perceived it as creating dependency and less likely to be perceived as promoting progress and development. As for North-South Korean relations, respondents perceive the USA as interfering with the unification of two Koreas. Finally, respondents perceive the USA as a superpower with imperialistic and dominating tendencies and they were less like to perceive the USA as promoting democracy and justice. Significant differences across the age groups have been found with the junior high school students holding the most negative view about the USA and their parents holding the most positive view of the USA. University students had mixed views of the USA. holding both positive and negative views of the USA. Those respondents with greater dissatisfaction of the political system and with less knowledge about the USA has more negative views of the USA.

• Korean Journal of Culture and Social Issue
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• v.10 no.1
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• pp.107-145
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• 2004

This study examines factors that influence delinquency among adolescents under probation using indigenous psychological analysis, focusing specifically on parent-child relationship. A total 268 adolescents under probation and their parents and 251 high school students and their parents participated in the two studies. In the first study, qualitative results indicate that both groups of adolescents were most likely to trust their parents than any other person and reason for their trust is reported to be based on blood relationship. Similarly, majority of parents of both groups reported trusting their children because of the blood relationship. Parents hope that their children will be sincere a person and will be able to maintain harmonious social relationship. Parents of adolescents under probation were more likely to report disobedience as being most problematic, whereas parents of high school students were more likely report providing social and financial support for their children's education as being the most difficult. In the second study, structured questionnaires were administered to the four groups and the following set of results were obtained. First, in terms of family background, the socio-economic status of adolescents under probation was lower, they are less likely to live with both parents or natural parents, and more likely to have ran away from home than high school students. Second, adolescents under probation are less likely to trust their parents and more likely to view their parents as being hostile. Third, parents of adolescents under probation were less likely to trust their children, more likely to view their relationship as being conflictual and hostile, and feel that they had to sacrifice for their children when compared with parents of high school students. Implications of these results for parent-child relationship and delinquency are discussed.

• Korean Journal of Culture and Social Issue
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• v.10 no.2
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• pp.103-137
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• 2004

This study examines the basis of trust in relationships by adolescents and their parents using the indigenous psychological approach. Using the indigenous methodology, adolescents were asked the reasons why they trusted their mother, father, friends, and teachers. Parents were asked why they trusted their children, spouse and their children's teachers. A total of 1,737 participants completed an open-ended survey: 579 adolescents (274 middle school and 305 high school students) and their parents (579 fathers) and (579 mothers). The results indicate that adolescents trust their parents because of their sacrifice, followed by consanguinity (i.e., blood relationship), respect, their trust in me, dependability, and their advice and counseling. The reasons why adolescents trust their teachers is because of the academic guidance they provide, unconditional trust of teachers, their concern and care, respect for teachers, advice and counseling they provide, they are like parents, and because of their sacrifice for the students. The reasons for trusting their friends are as follows: Dependability, closeness, unconditional trust of friends, their understanding of me, and their emotional support. The reasons why parents trust their children are: Children's sincerity, honesty, consanguinity, parents' expectation and communication with the children, children's obedience, and since they are diligent in their schoolwork. The reasons for trusting one's spouse are reported to be sincerity, their sacrifice for the family, honesty, unconditional trust of a spouse, and because of mutual support. The reasons why parents trust their children's teachers are reported as follows: Unconditional trust of teachers, their sacrifice for the students, and their sincerity. There were no significant differences across the type of school and academic grades in terms of trust of parents. However, middle school students are more likely to trust their teachers, and high school students are more likely trust their friends. The male students rather than female students and those students with higher academic grades are more likely to trust their parents, friends, and teachers. For parents, there were no significant differences across age, sex, and educational status concerning the trust of their children, spouse, and children's teachers. There was a positive correlations between parents' trust of their spouse and children and their children's trust of their parents. There was also a positive correlations of mothers' trust of children's teachers and the children's trust of their teachers.

• Korean Journal of Culture and Social Issue
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• v.10 no.3
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• pp.103-129
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• 2004

This article examines the Korean adolescents and adults' social representation and trust of Korean society and people using indigenous psychological analysis. Respondents were asked to write in an open-ended questionnaire their perception of the following five aspects: Korean politics, economy, society, culture and people. They were then asked to report why they trust or distrust Korean society. A total of 1,064 respondents (218 middle school students, 200 university students, 218 fathers of the middle school students, 218 mothers of the middle school students, and 210 teachers) completed a questionnaire developed by the present researchers. The data were collected during April to June, 2003. The results indicate that 94.5% of Koreans view the existing political system and politicians as being corrupt, inept, factional, and lacking in integrity. A vast majority (84.9%) recognize the existence of systemic problems in the Korean economy. A total of 78.2% see problems in Korean society being dominated by selfishness, factionalism, conservatism, and social uncertainty. For Korean culture, a majority of respondents report being proud of its cultural tradition, accomplishment, and creativity. At the same time, 45.7% report loss of cultural identity and pride due to external influences. More than half of the respondents report negative aspects of Korean people (i.e., selfish, lack of morality, rushed, and overly focused on their social image), while nearly half of the respondents report positive aspects of Korean people as being compassionate, cooperative, good-natured and hard-working. As for reason for trusting Korean society, around a third report "because it is our country," followed by its future potential, and the good-nature and willingness of Korean people to work hard. The reasons for distrusting Korean society is the dishonesty politicians, corruption, institutional ineptness, and economic uncertainty. These results indicate a low level of collective efficacy in influencing and affecting change in Korean society.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.325-334
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• 2023

The invasive red swamp crayfish, Procambarus clarkii, is native to south-central United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.179-192
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• 2023

In this study, changes in the microbial ecosystem of the Yeongheungdo island coastal waters were investigated for five years to collect basic data. To evaluate the influence of distance from the coast on the microbial ecosystem, four sites, coastal Site (S1) and 0.75, 1.5, and 3 km away from the coast, were set up and the changes in physicochemical and biological factors were monitored. The results showed seasonal changes in water temperature, dissolved oxygen, salinity, and pH but with no significant differences between sites. For nutrients, the concentration of dissolved inorganic nitrogen increased from 6.4 μM in April-June to 16.4 μM in July-November, while that of phosphorus and silicon phosphate increased from 0.4 μM and 2.5 μM in April-June to 1.1 μM and 12.0 μM in July-November, respectively. Notably, phosphorus phosphate concentrations were lower in 2014-2015 (up to 0.2 μM) compared to 2016-2018 (up to 2.2 μM), indicating phosphorus limitation during this period. However, there were no differences in nutrients with distance from the coast, indicating that there was no effect of distance on nutrients. Phytoplankton (average 511 cells mL^-1) showed relatively high biomass (up to 3,370 cells mL^-1) in 2014-2015 when phosphorus phosphate was limited. Notably, at that time, the concentration of dissolved organic carbon was not high, with concentrations ranging from 1.1-2.3 mg L^-1. However, no significant differences in biological factors were observed between the sites. Although this study revealed that there was no disturbance of the ecosystem, further research and more basic data on the microecosystem are necessary to understand the ecosystem of the Incheon.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.323-336
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• 2023

We investigated the nickel potential and genesis of ultramafic rocks in the Yugu area to secure nickel resources in South Korea. The Yugu ultramafic rocks, located in the southwest of the Gyeonggi Massif, are characterized by spinel peridotite and exhibit strong serpentinization along their boundaries. The serpentinization is observed as olivine transformed to antigorite and chrysotile, while pentlandite, the nickel sulfide mineral, altered into millerite and awaruite. Serpentine displays distinct foliation, aligning subparallel to the ultramafic rock boundaries and foliation of Yugu gneiss. This suggests that the uplift of ultramafic rocks resulted in hydrothermal infiltration likely sourced from the Yugu gneiss metamorphism. The Yugu ultramafic rocks are residues after 5~18% partial melting of abyssal peridotite. Enriched light rare earth elements and Eu imply secondary metasomatism. Geochemistry suggests a link between the formation of Yugu ultramafic rock and the Triassic collision of the North and South China continents. The nickel content is around 0.17~0.21%, mainly contained in olivine and serpentine. Hence, in addition to the mineral processing study on the sulfide minerals, focused studies on oxide minerals for enhanced nickel recovery within the Yugu ultramafic rock are strongly suggested.

• Korean Journal of Culture and Social Issue
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• v.8 no.1
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• pp.103-139
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• 2002

Korean society has significantly changed with the onset of a dramatic economic crisis in 1998. From 2000, however, the Korean economy has recovered and currently Korea is enjoying a similar standard of living and economic growth as the pre-1998 levels. This study is a follow-up analysis, comparing the results examining the success attribution of Korean students and adults in 2001 with the results obtained before the economic crisis in 1997. Using the indigenous psychological approach, this study compares the similarities and differences in Korean students and adults' attribution of their personal success before and after the economic crisis. A total of 988 participants, consisting of 481 primary, junior high, senior high and university students and 507 adults (236 fathers and 271 mothers of the students) completed the questionnaire developed by Kim and Park (1998). The results indicate that students perceived their academic achievement and adults perceived successful family life as their most proud achievement. Successful family life included items such as academic success of children, healthy development of their children, and harmonious family life. The person who provided the most significant support for students were parents and for adults, it was their spouse. For students, the importance of friends' social support increased during the high school years. In terms of type of social support, emotional support was reported to be the most important for both students and adults. As for the reason for their success, majority of students and men reported self-regulation and for women, supportive family environment was reported as being the most important. Comparing 2001 results with the 1997 results, the importance of family increased after the economic crisis. Even with the dramatic economic crisis, however, some of the underlying pattern remain strong (such as importance of academic achievement for students, family life for adults, the importance of social support, especially emotional social support from family members, and believing that self-regulation would lead to success). The similar pattern of results obtain before and after the economic crisis indicate that the above results reflect a fundamental values and belief system deeply imbedded in Korean mentality.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.187-195
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• 2023

Almost all of the water from agricultural dams located to the upper of the Yeongsan river is supplied as irrigation water for farmland and thus is not discharged to the main stream of the river. Also, most of the irrigation water does not return to the river after use, adding to the lack of flow in the main stream. As a result, the water quality and aquatic health of the river have become the poorest among the four major rivers in Korea. Therefore, in this study, several strategies for water quality improvement of the river were developed considering pollution reduction and flow rate increase, and their effect analysis was performed using a water quality model. The results of this study showed that the target water quality of the Yeongsan river could be achieved if flow increase strategies (FISs) are intensively pursued in parallel with pollution reduction. The reason is because the water quality of the river has been steadily improved through pollution reduction but this method is now nearing the limit. In addition, rainfall-related FISs such as dam construction and water distribution adjustment may be less effective or lost if a megadrought continues due to climate change and then rainfall does not occur for a long time. Therefore, in the future, if the application conditions for the FISs are similar, the seawater desalination facility, which is independent of rainfall, should be considered as the priority installation target among the FISs. The reason is that seawater desalination facilities can replace the water supply function of dams, which are difficult to newly build in Korea, and can be useful as a climate change adaptation facility by preventing water-related disasters in the event of a long-term megadrought.