• Cross-Cultural Studies
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• v.45
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• pp.269-293
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• 2016

This research studies the characteristics of the family systems of traditional societies in Black Africa. For this purpose, this study has chosen three subtopics: the distinctive features of traditional societies, marriage customs (polygamy and polyandry), and the societal features of patriarchal and matriarchal societies. First, we analyze men's and women's roles, ownership and management of the land, dowry, and social values of livestock as the distinctive features that support the family system in traditional Black African societies. These elements play an important role in increasing the number of family members. Next we analyze marriage customs-polygamy and polyandry-which increase the number of family members, on the one hand, and secure the labor force, on the other hand. Most traditional societies in Black Africa prectice polygamy. However, the $Bashil{\acute{e}}l{\acute{e}}$ and Bahima prectice polyandry. Polygamy in traditional societies in Black Africa is based on the traditional social customs that display the authority and dignity of the family head, who has control over all family members in both patrilineal and matrilineal societies. The authority and dignity of the family head are used to keep and increase the number of family members, that is, to secure the community firmly. Finally, most traditional societies are patrilineal. However, matrilineal societies are prevalent in the so-called Matrilineal Belt, which term refers to the savanna regions where Bantu peoples reside, that is, the coastal regions from the Angolan coast, bordering the Atlantic, to the Tanzanian and Mozambique coasts that border the Indian Ocean. These societies trace descent through the maternal bloodline. The traditional family system in Black Africa is based on economic social, and political factors, as well as on the community spirit of the members, which has resulted from the choices made to increase the prosperity and well-being of the people.

• Korea journal of population studies
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• v.28 no.2
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• pp.33-62
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• 2005

This study aims to explain the current upheaval in marriage that many young Korean men and women postpone or deny their marriage. In order to explain the delayed marriage, we need to understand the taste by which men and women choose their partners, the opportunity by which they find their ideational half in reality, and the context in which these values and opportunities of marriages intersect. This study examines the way in which the value and opportunities of marriage among Korean men and women have intersected differently in the changing economic conditions. Using KLIPS(Korea Labor Income Panel Survey, 1998-2002), differential effects of education and occupational status on marital time according to marriage cohort and gender are analyzed. Results find that the opportunity of marriage among men turns out to have been stratified significantly according to their educational achievement and labor status since the 1990s. For women, education and economic activities are likely to influence marriage decision in a discordant way; during the period of 1990-997, highly educated women are more likely than their counterparts to be married earlier while there is no significant difference according to economic activities. This implies that status homogamy has been intensified since the 1990s and many women with high motivation for social status are able to achieve a vicarious social status through marriage in a prosperous economy. For women married after 1998, however, the educational effect is insignificant but economic activity contributes to delaying marriage. This suggests that under the economic restructuring since the late 1990s, the constraint of opportunities finding decent jobs particularly for men results in the contingent change in women's perception about family roles and economic activities by reducing their expectation to achieve a vicarious status through marriage, but increasing their motive for their own economic activities.

• Environmental and Resource Economics Review
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• v.23 no.3
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• pp.515-551
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• 2014

Recently, there has been a debate as to whether bioethanol should replace some portion of gasoline for fuels in South Korea, as energy security as well as climate change issues are rising as a significant national agenda. However, a considerable amount of subsidy will be required to compensate for the higher price of bioethanol-blended gasoline. In this context, government subsidy will obtain justification only when the positive social gains from consuming bioethanol for fuels can exceed the negative social costs. Through a nation-wide choice experimental survey, we examine if South Koreans have a positive value as well as non-linear preferences on substituting bioethanol for gasoline. The results reveal that the willingness to pay for purely domestic bioethanol-blended gasoline within 10% is about 52 KRW; Koreans have concave preferences on the blending ratio of bioethanol to gasoline. The turning point of the blending ratio of bioethanol was 6.5%. Also, we found inverse U-shaped curve between income and bioethanol choice probability and the turning point of the income was calculated as 250~299million KRW. Politically conservative propensity advocates uses of bioethanol blended gasoline, but awareness on bioethanol or more weights on environmental conservation have significantly negative effects on the choice of bioethanol. However, the design of the survey questionnaire is incompatible with the RFS of Korea and assumes orthogonality among the following four interrelated attributes: (i) domestic or offshore procurement of feedstocks in the case of domestic production, (ii) domestic production or import of bioethanol, (iii) the blending ratios, and (iv) the retail price increases. In addition, the results of model estimation and of model selection test are not definite. Hence, the results in this study should not be directly applied to the design of the specifics of the Korean RFS. Hence, the results in this study require cautions in applying to the design of the Korean RFS policy.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.1-10
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• 2020

The application of multiphase flows is increasingly being applied to analyze phenomena such as single phase flows where the fluid boundary changes continuously over time or the problem of mixing a liquid phase and a gas phase. In particular, multiphase flow models that take into account incompressible Newtonian fluids for liquid and gas are often applied to solve the problems of the free water surface such as wave fields. In general, multi-phase flow models require time-based the surface tracking of each fluid's phase boundary, which determines the accuracy of the final calculation of the model. This study evaluates the advection performance of representative VOF-type boundary tracking techniques applied to various CFD numerical codes. The effectiveness of the FCT method to control the numerical flux to minimize the numerical diffusion in the conventional VOF-type boundary tracking method and advection calculation was mainly evaluated. In addition, the possibility of tracking performance of free surface using CIP method (Yabe and Aoki, 1991) was also investigated. Numerical results show that the FCT-VOF method introducing an anti-diffusive flux to precent excessive diffusion is superior to other methods under the confined conditions in this study. The results from this study are expected to be used as an important basic data in selecting free surface tracking techniques applied to various numerical codes.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.99-108
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• 2022

Avian leukosis virus (ALV) is a highly contagious retrovirus that causes tumors and has resulted in great economic loss worldwide owing to its high transmission rate. Various ALV viral subgroups exist, with infections occurring via specific host receptors. The susceptibility or resistance of avian species to the ALV-A and K subgroups is determined by the host receptor, the tumor virus locus A (tva) gene, while that to ALV-B depends on another host receptor, the tumor virus locus B (tvb) gene. The resistance alleles of tva and tvb have primarily been identified in China, but none have beendetected in Korea. We analyzed the frequencies of tva and tvb genotypes in White Leghorn (WL), Korean Ogye (KO), and Korean native chicken (KNC) breeds, and assessed the resistance to ALV subgroups. In WL, both tva and tvb had various genotypes, including susceptibility and resistance alleles, whereas in KO, tva and tvb resistance alleles were dominant. In KNC, tva susceptibility and resistance alleles were mixed, whereas tvb resistance alleles were dominant. In addition, we showed that there were differences in the splicing pattern of tva transcripts and the expression level of tvb transcripts within breeds. Finally, we confirmed that ALV resistance depended on KO and KNC genotypes by in vitro infection of chicken embryonic fibroblasts with ALV. These results highlight that some KO and KNC individuals are naturally resistant to ALV subgroups A, B, and K, and will facilitate the preservation of economically superior traits through selective breeding.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.162-171
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• 1993

This paper deals with the anisotropy of the mushy region during solidification process of a binary mixture. A theoretical model which specifies a permeability tensor in terms of pricipal values is proposed. Also, the governing equations are modified into convenient forms for the numerical analysis with the existing algorithm. Some test computations are performed for soeidification of aqueous ammonium chloride solution contained in a square cavity. Results show that not only the present model is capable of resolving fundamental characteristics of the tranport phenomena, but also the anisotropy significantly affects the interdendritic flow structure, i.e., double-diffusive convection and macrosegregation patterns.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.4
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• pp.419-427
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• 2019

The application of ion crystallization technology was considered as a way to increase the operating efficiency and improve the operating performance of a liquid waste management system (LWMS) in the Advanced Power Reactor 1400 (APR 1400). Although ion crystallization technology has not been practically applied to Nuclear Power Plants (NPPs) until now, a previous experimental study demonstrated that it is possible to selectively remove at least 95% of various nuclide ions present in the liquid radioactive waste of NPPs. We reviewed the possibility of applying ion crystallization technology to the existing LWMS by applying the nuclide removal rate of ion crystallization technology and prepared a way to improve the existing LWMS in the APR 1400. Furthermore, we determined the optimized application location of ion crystallization technology in the existing LWMS by considering decontamination characteristics of the ion crystallization technology and the existing LWMS design features and operating experiences. The application of ion crystallization technology to the liquid waste collection tank, where liquid radioactive materials are collected, will have the least impact on the existing design while providing the greatest improvement. It is expected that the application of ion crystallization technology to the current APR 1400 or new NPPs would increase the operating efficiency of the LWMS and result in an improvement of system performance.

• Land and Housing Review
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• v.15 no.2
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• pp.39-56
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• 2024

This study addressed housing issues among various social problems of youth. With a focus on residential independence, this study analyzed the factors that lead youth to achieve residential independence. This study drew on nationwide data from the 'Youth Life Survey (2022)' with a sample size of 12,578. Binary logistic regression analysis was employed, with the dependent variable being residential independence. Key factors were as follows. The probability of residential independence was higher for men than women. Residential independence occurred mainly in non-metropolitan areas compared to metropolitan areas. Findings revealed that greater age, income, and assets facilitate achieving residential independence. In addition, public transport and cultural facilities were important for their residential independence, and it was found that the previous experience of residential independence had a positive effect. Policy implications derived from the findings are as follows. It is required to consider the heterogeneity and diversity of youth rather than implementing unitary policies. To ensure continuity and sustainability of self-reliance, long-term support programs are needed rather than temporary support. Moreover, it is required to offer public support comprehensively, instead of youth relying on support from personal networks, including their parents. An inclusive housing policy should be established to support youth for their residential independence in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.104-115
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• 1992

The rice culture techniques included 'Jodosukyungbeob'(旱稻水耕法 : culture techniques of early-ripening paddy rice), 'Mandosukyungbeob' (晩稻水耕法) : culture techniques of late-Ripening paddy rice 'Handobeob'(旱稻＆lt;山稻＆gt;法 : culture techniques of upland rice), 'Myojongbeob'(苗種法 : culture techniques of paddy rice by transplanting), 'Kunangbeob'(乾秧法 : culture techniques of rice by transplanting which rears seeding in dry paddy) and 'Sudogunpanongbeob'(水稻乾播農法 : culture techniques of paddy rice seeding in dry field). Especially, 'Kunangbeob' and 'Sudogunpanongbeob' were originally developed in Korea as seen in 1600s(Kyoungje : 經濟) and early 1800s (Yoji : 要旨). In 'Jodosukyungbeob' it took 9 days for seed dipping, water-sprouting and prevent damage by birds, each for 3 days in China, but in Korea seed dipping in water took 3 days and the rest of the procedures were flexibly established. In matured soils, practices were fall plowing right after harvest, recognition of effective tillering and additional fertilization use of human manure, and stimulation of sprouting by lime application. The unique culture techniques adequate for Korean situations were practiced, which included weed control after draining accurately for 3 to 4 times, draining at mid season for improving wind and drought tolerance, rice harvesting at appropriate time for preventing grain shattering, and seeding in rows. 'Mandosukyungbeob' was improved techniques contrast to those of China, and the major contents were selection of proper varieties, good stand establishment by seeding high rates, induction of vigorous tillers, and adoption of 'Jokjongbeob'(足種法 : seeding method by foot). Also, one of the most prominent rice cultures by our ancestors was 'Kunpanongbeob' that was systemized form habitual practice of Pyongan Province. The unique technique actualized was 'Hando [旱稻(山稻)]' culture technique which was the combinations of 'Jokjongbeob', root stimulation method, and disaster-tolerant mixture cropping with adoptation of variety theory, although it was originated from China. The transplanting techniques has come before 'Jikseol'($\ulcorner$直說$\lrcorner$) and its merits were sufficiently realized. However, this method was basically prohibited from the early Chosun dynasty because extremely bad harvest was expected under drought conditions and insufficient conditions of water storage. But, it was permitted in the areas that contained water all the times and in case of large-scale farming especially. Most of rice culture was transplanted in the end of the Chosun dynasty because transplanting was continuously spreaded in the three southern provinces of Korea. Under these circumstances, transplanting technique was improved from the early to the end of the Chosun dynasty by weed control, fertilizing, water management, and quadratic transplanting. Based on these techniques, agricultural productivity was improved 5 times by that time. 'Kunpanongbeob' was created and developed properly for Korean conditions that is dry in early season and flooding in late season. This was successively developed and established into transplanting technique of nursery seedling.