• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1719-1728
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• 2017

Recent concerns about environmental conditions have triggered the growing interest in using green energy resources. These sources of energy, however, bring new challenges mainly due to their uncertainty and intermittency. In order to alleviate the concerns on the penetration of intermittent energy resources, this paper investigates impacts of realizing demand-side potentials. Among different demand-side management programs, this paper considers demand response wherein consumers change their consumption pattern in response to changing prices. The research studies demand response potentials from different load sectors on generation system well-being. Consumers' sensitivity to time-varying prices is captured via self and cross elasticity coefficients. In the calculation of well-being indices, sequential Monte Carlo simulation approach is accompanied with fuzzy logic. Finally, IEEE-RTS is used as the test bed to conduct several simulations and the associated results are thoroughly discussed.

• Korean Journal of Human Ecology
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• v.14 no.1
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• pp.133-141
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• 2005

This research was designed to investigate the effect of a hand and a sensibility image on the preference to skirt textiles. 131 male and female college students were surveyed and 10 kinds of preferred fabrics were used each as a specimen for all 4 seasons. Factor analysis, t-test, Pearson's correlation, and regression were used for a statistical analysis by SPSS WIN 10.0. The results of this study are as follows: 1. In spring/fall season, 6 factors including 'elasticity/flexibility' were extracted as a hand factor, and 2 factors including 'modern elegance' were extracted as a sensibility factor in skirt textiles. 2. In summer season, 5 factors such as 'unevenness/stiffness' were extracted as a hand factor and 2 factors such as 'modern elegance romantic' as a sensibility image. 3. In winter season, 7 factors including 'elasticity' were extracted as a hand factor and 2 factors including 'modern elegance romantic' as a sensibility image. 4. Significant correlations existed between a hand and a sensibility image in spring/fall, summer, and winter. 5. A sensibility image was one of the important factors in the preference to skirt textiles in spring/fall, summer, and winter.

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.190-200
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• 1994

The purpose of this research is to examine experimentally the mechanical properties and economics of No-fines concrete for its application to the low-rise housing construction. Basic mechanical properties of No fines concrete are studied by measuring of compressive, tensile strength and stress-strain relationship, and economics of it is compared with other materials in unit cost and wall construction cost. From the test results, it can be concluded that No-fines concrete has advantages of good workability, light weight and lower construction cost, even though it has lower strength and modulus of elasticity than normal conc:rt:te does.

• Computers and Concrete
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• v.12 no.1
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• pp.53-64
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• 2013

The curing temperature is known to influence the rate of mechanical properties development of early age concrete. In realistic sites the temperature of concrete is not isothermal $20^{\circ}C$, so the paper measured adiabatic temperature increases of four different concretes to understand heat emission during hydration at early age. The temperature-matching curing schedule in accordance with adiabatic temperature increase is adopted to simulate the situation in real massive concrete. The specimens under temperature-matching curing are subjected to realistic temperature for first few days as well as adiabatic condition. The mechanical properties including compressive strength, splitting strength and modulus of elasticity of concretes cured under both temperature-matching curing and isothermal $20^{\circ}C$ curing are investigated. The results denote that comparing temperature-matching curing with isothermal $20^{\circ}C$ curing, the early age concretes mechanical properties are obviously improved, but the later mechanical properties of concretes with pure Portland and containing silica fume are decreased a little and still increased for concretes containing fly ash and slag. On this basement using an equivalent age approach evaluates mechanical properties of early age concrete in real structures, the model parameters are defined by the compressive strength test, and can predict the compressive strength, splitting strength and elasticity modulus through measuring or calculating by finite element method the concreted temperature at early age, and the method is valid, which is applied in a concrete wall for evaluation of crack risking.

• Korea-Australia Rheology Journal
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• v.13 no.1
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• pp.37-45
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• 2001

Numerical simulation of coextrusion process of viscoelastic fluids within a die has been carried out. In the coextrusion process velocity profile at the outflow boundary is not known a priori, which makes it difficult to impose the proper boundary condition at the outflow boundary. This difficulty has been avoided by using the open boundary condition (OBC) method. In this study, elastic viscous stress splitting (EVSS) formulation with streamline upwind (SU) method has been used in the finite element method. In order to test the validity of the OBC method, comparison between the results of fully developed condition at the outlet and those of OBC has been made for a Newtonian fluid. In the case of upper convected Maxwell (UCM) fluid, the effect of outflow boundary condition on the interface position has been investigated by using two meshes having different downstream lengths. In both cases, the results with the OBC method showed reasonable interface shape. In particular, for the UCM fluid the interface shape calculated with OBC was independent of the downstream length, while the results with the zero traction condition showed oscillation of interface position close to the outlet. Viscosity difference was found to be more important than elasticity difference in determining the final interface position. However, the overshoot of interface position near the con-fluent point increased with elasticity.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.87-101
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• 1990

This study was undertaken to test to fit forms of the Engel curves to data. The comparisons were confined to the linear, semi-logarithmic and double-logarithmic forms. Data from the 1970-1987 Urban Household Economy Survey were used to estimate the Engel curves. The twelve categories of consumption expenditure were considered for investigation. Parameters of the Engel curves were derived from OLS and TSLS. In this paper the size of the family was used as the deflater. The results could be summarized as follows: 1. Comparing with the R2 of three foms, it could be concluded that, the linear form generally gave a better fit to data than the other forms did. Only for housing and clothing and foot wear, did the semi-logarithmic form give a better fit. Only for meals outside the home, fuel, light and water charges, and miscellaneous, did the double-logarithmic form give a better fit. 2. Comping with the income elasticities based on the alternative forms, it could be concluded that the differences between the estimates were since each form made different assumption as to the way in which elasticity varied. In general, the semi-logarithmic form gave the highest estimate and double-logarithmic form did the lowest estimate. The difference between semi-logarithmic and the other forms were greater than the those of linear and double-logarithmic form. 3. It was found that the income elasticity varied with the difinition of income used as an explanatory variable in Engel curves.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.294-300
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• 1999

After researching the physical properties of the concrete included Rice Husk Ash(RHA concrete) and workability of fresh concrete admixed RHA, we have tested durability of RHA-concrete against freeaing and thawing in the winter using rapid freezing and thawing test method(KS F 2456) . There aretwo hypotheses to explain the failure mechanism of a freezing and thawing action. First, the hydraulic pressure in the pores of freezing concrete make an internal stress of concrete structures outbreaking micro crack in the face of concrete, Second, Frost action causing damage to cement paste repeatedly come from soil frost action, freezing water in the capillaries. Initial Relative Dynamic Modulus of Elasticity (DME) was biggest in cae of unit binder weight 600kgf/㎥ and relative dynamic modulus of elasticity increased until 300cycles. In general , initial relative DME was proportional to unit binder weight . Relative DME was decreased in proportion to unit binder weight in the case of 300, 400, 500kgf/㎥ , but relative DME fo the others remained more than 90% until 300 cycles. It was not good effect of intermixed RHA to concrete in case of below unit binder weight 300kgf/㎥ and the resistance of freezing and thawing was not good either.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.143-150
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• 2004

In this paper, resonant ultrasound spectroscopy(RUS) was used to determine the natural frequency of a ceramic ferrule and a ball lens. The ceramic ferrules are cylinderical shape with $\phi$ 2.56mm diameter and l0mm in length. Crack lengths of these ferrules are 10.40$\mu$m, 21.18$\mu$m and 32.35$\mu$m. The spherical ball lens was made of BK-7 glass, one's diameter in 2mm and 5mm. RUS system is consisted of spectrum analyzer, power amplifier, PZT sensor and support frame. The principle of RUS is that the mechanical resonant frequency of the materials depends on density and the coefficient of elasticity. Rus system is based on that given resonant frequency of the materials can be represented by the function of density and the coefficient of elasticity, and it is applied to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and defective ones. Defect evaluation by RUS are performed to investigate the natural frequency measure of ferrule and ball lens.

• Advances in concrete construction
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• v.5 no.6
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• pp.575-586
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• 2017

The disposal of polythene waste and fly ash is causing serious threat to the environment. Aim of this study is to decrease environmental pollution by using polythene waste and fly ash in concrete. In this study, cement was partially replaced with 0%, 5%, 10%, 15% and 20% fly ash (by weight) and plastic waste was added in shredded form at 0.6% by weight of concrete. The specimens were prepared for the concrete mix of M25 grade and water to cementitious material ratio (w/c) was maintained as 0.45. Fresh concrete property like workability was examined during casting the specimens. Hardened properties were found out by carrying out the experimental work on cubes, cylinders and beams which were cast in laboratory and their behavior under test were observed at 7 & 28 days for compressive strength and at 28 days for density, flexural strength, dynamic modulus of elasticity, abrasion resistance, water permeability and impact resistance. Overall results of this study show that addition of 0.6% (by weight of the concrete) plastic waste with 10% (by weight of cement) replacement of cement by fly ash result an improvement in properties of the concrete than conventional mix.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.769-775
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• 2021

The objective of this research was to analyze the factors influencing the farm-gate shrimp prices in Thailand using monthly time series from January 2001 to December 2019. The econometric methodology was employed to satisfy the purpose, consisting of the cointegration test for revealing the long-run relationship and equilibrium elasticity between the variables as well as the error correction model for detecting speed adjustment to shock responses. The empirical results revealed that (1) the export shrimp prices, shrimp production in the country, and shrimp export volume indicated a long-run relationship running to the farm-gate shrimp prices in Thailand with the size of equilibrium elasticity equal to 1.083%, -0.256%, and 0.123, respectively, and (2) the farm-gate shrimp prices in Thailand would adjust to the equilibrium line with a speed equal to 20.147% if there was any kind of incident or shock which caused the relationship to deviate from the equilibrium point. There was no relationship in terms of global shrimp prices and the exchange rate for farm-gate shrimp prices in Thailand. The recommendations should emphasize the varieties of shrimp products for export to other countries beyond the main trading markets nowadays to reduce risks and fluctuations in the export prices of shrimp products.