• 한국노년학
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• v.27 no.2
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• pp.503-518
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• 2007

The intergenerational support exchange depends on elder's objective conditions and social context, and its effects are diverse. I argue that not only capacity such as health condition and economic status but also relational properties among parent(s) and adult children are important to determine their reciprocal support exchange. Seoul area is selected, and 730 elders are interviewed to be analyzed quantitatively. The survey data are collected based on the structured questionnaire. Findings are partly supportive to the arguments presented above. The relational properties, especially coresidence, the number of adult children, and contact frequency independently influence reciprocal support. The better health conditions of parent(s) are, the more support to adult children is given. The economic status is related to financial support exchange only. The types of intergenerational support exchange include dependant, balanced, and generalized reciprocity. The most important determinant of the reciprocity is the elders' health condition.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.448-462
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• 2021

Only a few studies investigated the relationship between exchange structure and solidarity in online communities and even reported conflicting results. This study attempts to shed lights on this relationship by introducing a moderating variable, i.e., exchange benefits, based on the social exchange theory. Also, distributed knowledge is considered as a determinant of exchange structure. The results of a field study from 380 online communities show that both direct and generalized exchange structures have positive effects on community solidarity, but their effects vary depending on the level of exchange benefits. When exchange benefits are high, generalized exchange influences community solidarity more than direct exchange does, whereas at a low level of benefits there are no significant differences between the two exchange structures. Also distributed knowledge turns out to be a significant influencer of generalized exchange.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.4
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• pp.799-814
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• 2009

A class invariant is the value of a modular function that generates a ring class field of an imaginary quadratic number field such as the singular moduli of level 1. In this paper, using Shimura Reciprocity Law, we compute the Galois actions of some class invariants from the generalized Weber functions $\mathfrak{g}_0,\mathfrak{g}_1,\mathfrak{g}_2$ and $\mathfrak{g}_3$ over quadratic number fields with discriminant $D{\equiv}1$ (mod 12).

• Journal of the Chungcheong Mathematical Society
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• v.24 no.4
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• pp.921-925
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• 2011

A class invariant is the value of a modular function that generates a ring class field of an imaginary quadratic number field such as the singular moduli of level 1. In this paper, using Shimura Reciprocity Law, we compute the Galois actions of a class invariant from a generalized Weber function $g_2$ over quadratic number fields with discriminant $D{\equiv}21$ (mod 36).

• Journal of the Chungcheong Mathematical Society
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• v.23 no.4
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• pp.853-860
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• 2010

A class invariant is the value of a modular function that generates a ring class field of an imaginary quadratic number field such as the singular moduli of level 1. In this paper, using Shimura Reciprocity Law, we compute the Galois actions of a class invariant from a generalized Weber function $g_2$ over quadratic number fields with discriminant $D{\equiv}-3$ (mod 36).

• Structural Engineering and Mechanics
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• v.32 no.3
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• pp.407-427
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• 2009

A fundamental solution for the transient, quasi-static, plane problems of linear viscoelasticity is introduced for a specific material. An integral equation has been found for any problem as a result of dynamic reciprocal identity which is written between this fundamental solution and the problem to be solved. The formulation is valid for the first, second and mixed boundary-value problems. This integral equation has been solved by BEM and algorithm of the BEM solution is explained on a sample, mixed boundary-value problem. The forms of time-displacement curves coincide with literature while time-surface traction curves being quite different in the results. The formulation does not have any singularity. Generalized functions and the integrals of them are used in a different form.

• Journal of Biomedical Engineering Research
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• v.26 no.4
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• pp.215-221
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• 2005

We describe the development of a prototype multi-channel electrical impedance tomography (EIT) system. The EIT system can be equipped with either a single-ended current source or a balanced current source. Each current source can inject current between any chosen pair of electrodes. In order to reduce the data acquisition time, we implemented multiple digital voltmeters simultaneously acquiring and demodulating voltage signals. Each voltmeter measures a differential voltage between a fixed pair of adjacent electrodes. All voltmeters are configured in a radially symmetric architecture to optimize the routing of wires and minimize cross-talks. To maximize the signal-to-noise ratio, we implemented techniques such as digital waveform generation, Howland current pump circuit with a generalized impedance converter, digital phase-sensitive demodulation, tri-axial cables with both grounded and driven shields, and others. The performance of the EIT system was evaluated in terms of common-mode rejection ratio, signal-to-noise ratio, and reciprocity error. Future design of a more innovative EIT system including battery operation, miniaturization, and wireless techniques is suggested.