• Korea journal of population studies
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• v.29 no.1
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• pp.97-131
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• 2006

This study analyses the relationship between mothers and adolescent children in current Korean society from an exchange perspective. Utilizing the 6 types of resources, I. e., service, goods, money, information, status, and affection, suggested by Foa et. al. and the distinction between positive exchange (rewards) and negative exchange (punishments), it explores what resources are exchanged, how the resources exchanged are valued by each party, whether the exchange is symmetrical or asymmetrical, and if gender and age of the child affects the exchange. A survey was conducted to 150 children--from middle school aged to college going, and their cohabiting mothers in the metropolitan Seoul. The overall findings are as follows: Positive exchanges are dominant over negative exchanges. The exchange of positive exchanges occur asymmetrically within each resource type, with the exception of affection which is exchanged in a more equal term. In general, children receive positive resources more often, but mothers value the resources given by their children more highly. Negative resources are exchanged in more symmetrical terms. Negative resources exchanged more frequently tend to have weaker negative valence. Daughters maintain a more intensive exchange relation with their mothers than sons do, and this pattern is especially prominent in the exchanges of information and affection. The age of the child has a weak effect on the exchange.

• Polymer(Korea)
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• v.31 no.3
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• pp.247-254
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• 2007

Heterogeneous anion exchange membranes were prepared by compression molding for the recovery of sulfate ion from waste water. The swelling ratio, transport number, and ion exchange capacity of the heterogeneous anion exchange membranes were increased and their electrical resistances were decreased as the amount of ion exchange resin content in the matrix was raised. The tensile strength of the heterogeneous anion exchange membrane was decreased with increasing the amount of ion exchange resin in the LLDPE. The tensile strength for the LDPE heterogeneous membrane containing 30 wt% anion exchange resin showed the highest value. The water content increased with increasing amount of ion exchange resin in the membrane. Moreover the highest transport number of the membrane was 0.86. The electrical resistance of LDPE matrix membrane with 50 wt% resin showed $46.5{\Omega}{\cdot}cm^2$. Current efficiency of electrodialysis for sulfate ion showed the highest value at the current density of $125 mA/cm^2$ in 0.5 mol/L sulfuric acids solution.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.745-751
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• 1998

The well-mixed room model has been traditionally used to predict the concentrations of contaminants in indoor environments. However, this is inappropriate because the flow fields in many indoor environments distribute contaminants non-uniformly, due to imperfect air mixing. Thus, some means used to describe an imperfectly mixed room are needed. The simplest model that accounts for imperfect air mixing is a two-zone model. Therefore, this study on development of computer program far the two-zone model is carried out to propose techniques of estimating the concentration of contaminants in the room. To do this, an important consideration is to divide a room into two-zone, i.e. the lower and upper zone assuming that the air and contaminants are well mixed within each zone. And between the zones the air recirculation is characterized through the air exchange parameter. By this basic assumption, the equations for the conservation of mass are derived for each zone. These equations are solved by using the computational technique. The language used to develope the program is a VISUAL BASIC. The value of air exchange coefficient($f_12$) is the most difficult to forecast when the concentrations of contaminants in an imperfectly mixed room are estimated by the two-zone model. But, as the value of $f_12$ increases, the air exchange between each zone increases. When the value of $f_12$ is approximately 15, the concentrations in both zone approach each other, and the entire room may be approximately treated as a single well-mixed room. Therefore, this study is available for designing of the ventilation to improve the air quality of indoor environments. Also, the two-zone model produces the theoretical base which may be extended to the theory for the multi-zone model, that will be contributed to estimate the air pollution in large enclosures, such as shopping malls, atria buildings, atria terminals, and covered sports stadia.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.15 no.26
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• pp.111-117
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• 1992

In the stock marketing. investor needs speedy and accurate decision making for the investment. A stock exchange index provides the important index of the early of 1993 in Korea using Fuzzy Delphi Method(F. D. M) which is widely used to a mid and long range forecasting in decision making problem. In the Fuzzy Delphi method, considerably qualified experts an first requested to give their opinion seperately and without intercommunication. The forecasting data of experts consist of Triangular Fuzzy Number (T.F.N) which represents the pessimistic, moderate, and optimistic forecast of a stock exchange index. A statistical analysis and dissemblance index are then made of these subject data. These new information are then transmitted to the experts once again, and the process of reestimation is continued until the process converges to a reasonable stable forecast of stock exchange index. The goal of this research is to forecast the stock exchange index using F.D.M. in which subjective data of experts are transformed into quasi -objective data index by some statistical analysis and fuzzy operations. (a) A long range forecasting problem must be considered as an uncertain but not random problem. The direct use of fuzzy numbers and fuzzy methods seems to be more compatible and well suited. (b) The experts use their individual competency and subjectivity and this is the very reason why we propose the use of fuzzy concepts. (c) If you ask an expert the following question: Consider the forecasting of the price index of stocks in the near future. This experts wi11 certainly be more comfortable giving an answer to this question using three types of values: the maximum value, the proper value, and the minimum value rather than an answer in terms of the probability.

• Polymer(Korea)
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• v.31 no.4
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• pp.315-321
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• 2007

Aminated PONF-9-GMA ion exchange fabrics were synthesized by radiation induced graft copolymerization. Hybrid ion exchange fabrics combined with aminated PONF-g-GMA fabrics and anionic ion exchange resin were also fabricated by hot melt adhesion method and then their adsorption properties were investigated. Ion exchange capacity of the hybrid ion exchange fabrics was higher than ion exchange fabric and was lower than bead resin. The maximum value was 4.18 meq/g. Adsorption breakthrough time for vanadium of the hybrid ion exchange fabric was 550 min, which was faster than bead resin but slower than fibrous ion exchanger. The Breakthrough time of the hybrid ion exchange fabrics gets longer with increasing pH. The initial breakthrough time occurred around 400 min with increasing vanadium concentration.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.283-291
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• 2018

Cracks in soil provide significant preferential pathways for contaminant transport and rainfall infiltration. Water exchange between the soil matrix and crack is crucial to characterize the preferential flow, which is often quantitatively described by a water exchange ratio. The water exchange ratio is defined as the amount of water flowing from the crack into the clay matrix per unit time. Most of the previous studies on the water exchange ratio mainly focused on cracked sandy soils. The water exchange between cracks and clay matrix were rarely studied mainly due to two reasons: (1) Cracks open upon drying and close upon wetting. The deformable cracks lead to a dynamic change in the water exchange ratio. (2) The aperture of desiccation crack in clay is narrow (generally 0.5 mm to 5 mm) which is difficult to model in experiments. This study will investigate the water exchange between a deformable crack and the clay matrix using a newly developed experimental apparatus. An artificial crack with small aperture was first fabricated in clay without disturbing the clay matrix. Water content sensors and suction sensors were instrumented at different places of the cracked clay to monitor the water content and suction changes. Results showed that the water exchange ratio was relatively large at the initial stage and decreased with the increasing water content in clay matrix. The water exchange ratio increased with increasing crack apertures and approached the largest value when the clay was compacted at the water content to the optimal water content. The effective hydraulic conductivity of the crack-clay matrix interface was about one order of magnitude larger than that of saturated soil matrix.

• Journal of the Korean Society for information Management
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• v.22 no.2 s.56
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• pp.165-184
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• 2005

Value and importance of online information are increased day by day as the knowledge and information society is emerging. However there is little study on information assessments due to the lack of the valid methodologies and models in this field. In this study we proposed a model of the economic value assessments for online information and utilized it to the contents of ITFIND which is an integrated IT information system supported by the MIC(Ministry of Information and Communication). We measured information value of ITFIND as follows: (1) both 'use value' and 'exchange value,' (2) annual $CS^{UV}\;and\;CS^{EV}$ per person by the category of each information, and (3) annual economic value of $CS^{UV}\;and\;CS^{EV}$ of ITFIND information based on it's users' annual $CS^{UV}\;and\;CS^{EV}$ per person.

• Journal of Magnetics
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• v.7 no.3
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• pp.80-93
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• 2002

The role of magnetic anisotropy of the antiferromagnetic layer on the magnetization process of exchange coupled polycrystalline ferromagnetidantiferromagnetic bilayers is discussed. In order to elucidate the magnetic torque response of Ni-Fe/Mn-Ir bilayers, the single spin ensemble model is newly introduced, taking into account the two-dimensionally random distribution of the magnetic anisotropy axes of the antiferromagnetic grains. The mechanism of the reversible inducement of the exchange anisotropy along desirable directions by field cooling procedure is successfully explained with the new model. Unidirectional anisotropy constant, J$k$, of polycrystalline Ni-Fe/Mn-Ir and Co-Fe/Mn-Ir bilayers is investigated as functions of the chemical composition of both the ferromagnetic layer and the antiferromagnetic layer. The effects of microstructure and surface modification of the antiferromagnetic layer on JK are also discussed. As a notable result, an extra large value of J$k$, which exceeds 0.5 erg/cm$^2$, is obtained for $Co_{70}Fe_{30}Mn_{75}Ir_{25}$ bilayer with the ultra-thin (50${\AA}$∼100${\AA}$) Mn-Ir layer. The exchange anisotropy of $Co_{70}Fe_{30}$ 40 ${\AA}/Mn_{75}Ir_{25}$ 100 ${\AA}$ bilayer is stable for thermal annealing up to $400{^{\circ}C}$, which is sufficiently high for the application of spin valve magnetoresistive devices.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.162-170
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• 2016

The key exchange protocols are very important to provide the secure communication in broadband satellite access network. However key exchange protocol of ETSI(European Telecommunications Standards Institute) is vulnerable to man-in-the-middle-attack by using Diffie-Hellman algorithm. And the key exchange protocol using certification is not useful in satellite environment. We propose the key exchange protocol using Timestamp which have the resistant to man-in-the-middle-attack. Proposed protocol is able to prevent the man-in-the-middle-attack by calculated time value. Also showing experiment results, we prove that proposed protocol improve memory usage, communication amount and calculation amount than other protocols.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.2
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• pp.31-38
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• 2011

The domestic rural villages have faced on the many problems in future society. The major purposes of this paper are to clarify in space program for the Rural Activating through the Urban-Rural Exchange. Firstly, it has examined the rural amenities of rural resources, such as natural surroundings, culture, history, landscape, economy, community power etc. Secondary, it was checked about analysis of operation programs corresponding to the rural resources. Thirdly, These space program of Urban-Rural Exchange, which has been archived process of spacial planning, was investigated the spacial conditions corresponding to the operation programs. To make Urban-Rural Exchange Center, it was necessary to analyze physical spacial size of building gross area, by data of cross checking with the area per capita and area per household in the rural village. According to the research, Urban-Rural Exchange Center was to be included visiting center, multipurpose room and dining room, exhibiting space, conference room, experience room, welfare space and specialized room with activation of rural village. However additional conditions are required that it is based on the sustainable development, environmentally friendly architecture both operation program and space program for the value of common society, citizen and villagers.