• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2148-2158
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• 1996

Uncoupled, quasi-static and linear thermoviscoelastic problems are analyzed in time domain by the finite element approximation which is developed using the principle of virtual work and viscoelasticity matrices instead of shear and bulk relaxation functions as in usual formulations. The material is assumed to be isotropic, homegeneous and thermorheologically simple, which means that the temperature-time equivalence postulate is effective. The stress-strain laws are expressed by relaxation-type hereditary integrals. In spatial and time discritizations, isoparametric quadratic quadrilateral finite elements and linear time variations are adopted. For explicit derivations, the viscoelastic material is assumed to behave standard linear solid in shear and elastically in dilatation. Two-dimensional examples are solved under general temperature distributions T = T(x, t), and compared with other opproximate solutions to show the versatility of the presented analysis.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.12-20
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• 2011

Oxy-coal combustion for $CO_2$ capture in coal power plants entails a mode switching from air-firing to oxyfiring. In this study, procedure of the mode switching was investigated and discussed through experiments in pilot scale facilities: (1) a 0.3 $MW_{th}$ furnace with a vertical single burner and a FGR(Flue Gas Recirculation) system (2) a 1 $MW_{th}$ furnace with horizontal 4 burners and a FGR system. Principle of the mode switching was established and performed with control of FD fan, FGR fan, ID fan and oxygen flow rates. We have found that equivalence ratio in the oxy-firing mode should be increased more than that in the air-firing to achieve stable mode switching. Control of FD, ID and FGR fans should be performed carefully in the mode switching, in the sense of complete combustion and flame attachment. Moisture contents in the ash and the flue gas recycled to the primary oxidizer stream should be removed to prevent condensation, corrosion and duct clogging.

• Structural Engineering and Mechanics
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• v.57 no.4
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• pp.681-701
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• 2016

This paper presents an experimental study of six steel reinforced high strength concrete T-shaped short-limb shear walls configured with T-shaped steel truss under low cyclic reversed loading. Considering different categories of ratios of wall limb height to thickness, shear/span ratios, axial compression ratios and stirrup reinforcement ratios were selected to investigate the seismic behavior (strength, stiffness, energy dissipation capacity, ductility and deformation characteristics) of all the specimens. Two different failure modes were observed during the tests, including the flexural-shear failure for specimens with large shear/span ratio and the shear-diagonal compressive failure for specimens with small shear/span ratio. On the basis of requirement of Chinese seismic code, the deformation performance for all the specimens could not meet the level of 'three' fortification goals. Recommendations for improving the structural deformation capacity of T-shaped steel reinforced high strength concrete short-limb shear wall were proposed. Based on the experimental observations, the mechanical analysis models for concrete cracking strength and shear strength were derived using the equivalence principle and superposition theory, respectively. As a result, the proposed method in this paper was verified by the test results, and the experimental results agreed well with the proposed model.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.9-14
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• 2015

In this paper, we analysis the electromagnetic scattering of an arbitrary shape dielectric cube subjected to plane wave incidence in three dimensions. MoM(Method of Moments)in which a surface of a body is divided with small triangular patches and equivalence principle are used to fuse the PMCHW(Poggio, Miller, Chang, Harrington, and Wu) Integral Equations with respect to equivalent currents on a dielectric body. Triangular patch and loop-patch basis functions that is robust in wide frequency ranges are used for MoM formulations. Proposed method is very useful to analysis the induced current of arbitrary dielectric bodies and numerical results for a dielectric cube are presented.

• Journal of Wellbeing Management and Applied Psychology
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• v.2 no.1
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• pp.9-19
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• 2019

The uniqueness of labour as a factor of production is that labour services cannot be separated from the employee. However, since the object of sale is only the services of the employee, not an employee himself, the labour conditions, determined by the labour and collective agreements or other agreements concluded at other levels and within the current legislation, are equally important. Speaking as a subject of labour, a person can realize his or her labour potential by the way of self-employment, that means to act as an independent producer seller of their products. Another way of labour potential realization is hiring, that means offering of the services as a hired employee to the employer, who is the subject of ownership. In this case there is an exchange under the principle: qualification and working time of the worker - for wages and profits. Each enterprise is confronted with a set of goals, among them - economic and social leadership. For their achievement the company uses all the available arsenal of resources - material, land, financial, labour. This indicates the equivalence of all types of resources in achieving the goal. But this is not quite true, because every resource can be included in production only through the activity of labour and people. And this activity depends on the attitude of the company to its employees, the degree of their motivation and stimulation.

• Korea Trade Review
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• v.46 no.2
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• pp.107-119
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• 2021

Using a trade policy, government can shift profits from foreign firms to domestic firms. This paper will reexamine how asymmetric information can affect the equivalence of tariff and quota in a duopoly, where one domestic firm competes with one foreign firm. It can happen that the domestic firm has informational advantage against the government. Within this framework, the domestic firm has private information about own marginal cost as well as the foreign firm's. The domestic firm would exploit the advantage to draw a favorable policy from the government. When the government is misled, social welfare would decline. This paper will guide how the government can extract information from the domestic firm by offering a menu of tariff or quota. Previous studies showed that quota demands information more than tariff. With the principle of revealed information, the domestic firm chooses tariff (quota) if the marginal cost of foreign firm is low (high). The quota level will be high (low) if the marginal cost of domestic firm is high (low). To prevent misrepresentation, the domestic firm should be charged when quota is implemented. When the quota level is low, the domestic firm is charged additionally. This paper can contribute to the literature of trade policy and information.

• Steel and Composite Structures
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• v.18 no.4
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• pp.853-871
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• 2015

Up to now, Japan has more than 200 corrugated steel web composite beam bridges which are under construction and have been constructed, and China has more than 30 corrugated steel web composite beam bridges. The bridge type includes the simply supported beam, continuous beam, continuous rigid frame and cable stayed bridge etc. The section form has developed to the single box and multi-cell box girder from the original single box and single chamber. From the stress performance and cost saving, the span range of 50~150 m is the most competitive. At present, the design mostly adopts the computational analytical method combining the spatial bar system model, plane beam grillage model and solid model. However, the spatial bar system model is short of the refinement analysis on the space effect, such as the shear lag effect, effective distribution width problem, and eccentric load factor problem etc. Due to the similarity of the plane beam grillage method in the equivalence principle, it cannot accurately reflect the shearing stress distribution and local stress of the top and bottom plates of the box type composite beam. The solid model is very difficult to combine with the overall calculation. Moreover, the spatial grid model can achieve the refinement analysis, with the integrity of the analysis and the comprehensiveness of the stress checking calculation, and can make up the deficiency of the analytical method currently. Through the example verification of the solid model and spatial grid model, it can be seen that the calculation results for the stress and the displacement of two models are almost consistent, indicating the applicability and precision of the spatial grid model.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.182-190
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• 2007

Virtual world is the 3D graphical interactive environment that networked by electronic communications. Virtual Worlds offered flow experience for a long time to their users. They blur the boundaries of work and play, so bring out the concept of Fun Labor. If we can accept the principle of equivalence between Fun Labor and Real Labor, the Fun Labor may be one of the solutions of the large unemployment problem in the information society. And the Fun Labor is the new type of labor that corresponds the subjectivity of users who want interesting experience as much as they spend money and times. This situation means that the users of Virtual worlds are structuring the identities as the Residents who act the Fun Labor. It'll be very important to examine the social effects of this situation.

• Journal of Families and Better Life
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• v.20 no.4
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• pp.89-102
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• 2002

Genetically modified foods may be defined as the foods deemed as safe by current technology among the many kinds of agricultural and stockbreeding products that are now under research and development using contemporary gene-modification techniques. This study examines hotly debated arguments, both for and against genetically modified- foods, in various countries. This study also investigates consumers'rights and responsibilities. Countries that are developing and exporting genetically modified organisms(GMO) have maintained that GMO can help produce more crops while reducing labor and other production-related costs, and that the genetically modified foods signify ″the second green revolution,″ which will solve future food and environmental problems by strengthening specific nutritive substances and extending shelf-life. But consumer groups, environmental organizations. and food-importing countries are more cautious about importing and consuming those foods because the potential dangers of GMO to human bodies and the environment have not been tested thoroughly yet. South Korea, following suit with others such as EU, Japan, Australia, and New Zealand, introduced a law on 'Labeling of Genetically Modified Foods', which went in effect in March, 2001, on the basis of customers'rights to make informed choices. The law takes the ″precautionary principle″ into consideration, rather than stopping at insuring ″substantial equivalence″ in developing and consuming GM foods. The actual impact of the law will depend on the level of citizens'Participation more than on the government's willingness to carry out the law. So far the level of Korean consumers'consciousness about genetically modified foods is very low. Therefore, it is hard to expect consumers to exercise their ″rights not to buy″ foods that are potentially unsafe. The Korean government must devise an effective plan to inform and educate the people about the labeling of genetically modified foods.

• Coupled systems mechanics
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• v.12 no.3
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• pp.199-220
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• 2023

This article presents a new analytical model to study the effect of porosity on the shear correction factors (SCFs) of functionally graded porous beams (FGPB). For this analysis, uneven and logarithmic-uneven porosity functions are adopted to be distributed through the thickness of the FGP beams. Critical to the application of this theory is a determination of the correction factor, which appears as a coefficient in the expression for the transverse shear stress resultant; to compensate for the assumption that the shear strain is uniform through the depth of the cross-section. Using the energy equivalence principle, a general expression is derived from the static SCFs in FGPB. The resulting expression is consistent with the variationally derived results of Reissner's analysis when the latter are reduced from the two-dimensional case (plate) to the one-dimensional one (beam). A convenient algebraic form of the solution is presented and new study cases are given to illustrate the applicability of the present formulation. Numerical results are presented to illustrate the effect of the porosity distribution on the (SCFs) for various FGPBs. Further, the law of changing the mechanical properties of FG beams without porosity and the SCFare numerically validated by comparison with some available results.