• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.109-113
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• 2002

Urban public service is goods and activities which satisfy public demands for the political, social, economic, cultural activity and household affairs of individual or groups and which urban government supply with free of charge. In view of government, in addition to fairness of facilities location, location of such facilities are to be determined the respect to cost of locating facilities and developmental direction in the future. Therefore, it is necessary to study on feasibility. A feasibility study Is an effective tool in determining the decision of investment or not and the level of investment priority on Projects requiring a sizeable investment and the feasibility of a project. The first, it is to select reasonable location. It was selected four and two by consideration of facilities distribution and connection with others. Six proposal selected was estimated by five element of approach, demand, symbol, reality, environment. In result proposal I was chosen. The next, it is to estimate scales. The finally, it is to study on economical efficiency. Net Present Value was came out ￦4.4billion by 20years and Inter Rate of Return showed up 11%. in addition, it offer various benefit by public facilities. In conclusion, this project is reasonable.

• Journal of the Korean Solar Energy Society
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• v.23 no.1
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• pp.57-67
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• 2003

This study aims to presents Evaluation Method of Green Remodeling that analyze the value of environment through expense, using the method of life cycle cost and life cycle assessment simultaneously. The results of this study are summarized as follows. Evaluation Model developed in this study can convert economical value of environment into cost by integrating. In addition, the model can apply as a useful tool to estimation of economical design alternative as well as quantification of environmental loads and costs. Evaluation Model presented In this study observe energy consumption and the environmental load emission with qualification, it can forecast effect of environmental cost that cost estimation is expected to be added to energy cost rate by being possible. Synthetically, when Estimation Model and computer program that developed in this study is applies to the construction industry; reasonable management of environmental load is convenient at each step of Green Remodeling. In addition, at preliminary design phase, practical use may be possible by reasonable yardstick about various alternatives and improvement of design alternatives likewise by grasping environmental effect.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.576-581
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• 2008

Electricity Market in Korea can't provide locational price signal through energy price because energy market is CBP(Cost Based Pool) using uniform price. Generators don't want to locate in a densely populated load area(like the metropolitan area). Because they are paid more fixed cost in metropolitan area. This situation has loss and congestion occurred in power system. However energy market without price signal can't lead generator to the metropolitan. So, market participants should be provided price signal through the transmission price instead of energy price. This paper proposes transmission pricing method considering reliability cost in order to offer price signal. Also, it proposes the method to allocate the transmission cost to each transmission line user through a fair and a reasonable manner. The transmission price is decided by the reliability value of each line. If a transmission line of high reliability value is broke, users using that line will get a loss and a discomfort. So, it is fair that users using a transmission line of high reliability value pay more than the other users. Also, it is reasonable that a transmission line owner get paid more form users using that line.

• ETRI Journal
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• v.46 no.2
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• pp.227-237
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• 2024

This study proposes a novel, conditionally applied neural network technique to reduce the overall peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system while maintaining an acceptable bit error rate (BER) level. The main purpose of the proposed scheme is to adjust only those subcarriers whose peaks exceed a given threshold. In this respect, the developed C-ANN algorithm suppresses only the peaks of the targeted subcarriers by slightly shifting the locations of their corresponding frequency samples without affecting their phase orientations. In turn, this achieves a reasonable system performance by sustaining a tolerable BER. For practical reasons and to cover a wide range of application scenarios, the threshold for the subcarrier peaks was chosen to be proportional to the saturation level of the nonlinear power amplifier used to pass the generated OFDM blocks. Consequently, the optimal values of the factor controlling the peak threshold were obtained that satisfy both reasonable PAPR reduction and acceptable BER levels. Furthermore, the proposed system does not require a recovery process at the receiver, thus making the computational process less complex. The simulation results show that the proposed system model performed satisfactorily, attaining both low PAPR and BER for specific application settings using comparatively fewer computations.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.555-563
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• 2024

The reasonable setting of coal pillar width plays a key role in guaranteeing the steadiness of surrounding rock of fully mechanized caving gateroad driving along the next goaf. Based on the engineering background of the Bayangaole mine, the discrete element method was used to simulate the fracture evolution of coal pillars with different pillar widths. The results show that the damage rate of the coal pillar increases with the decrease in the width of the coal pillar. Once the coal pillar width is smaller than 6 m, cracks run through the coal pillar, and the coal pillar is completely damaged. In the middle of the coal pillar, which has a width of 6 m and above, there is a relatively complete area with low damage. The results show that the pillar width of 6 m is the most appropriate. Field tests prove that the reserved width of a 6 m small coal pillar can effectively control the surrounding rock deformation, ensuring the overall steadiness of the gateroad in the thick coal seam. It is hoped that this study will offer some reference for the determination of the reasonable size of the coal pillar.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.04a
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• pp.38-43
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• 1989

An improved model for predicting the reinforced concrete element behavior under dynamic strain rates was developed using the layer modeling technique. The developed strain rate sensitive model for axial/flexural analysis of reinforced concrete elements was uses to predict the test results, performed at different loading rates, and the predictions were reasonable. The developed analysis technique was used to study the loading rate sensitivity of reinforced concrete beams and columns with different geometry and material properties. Two design formulas for computing the loading rate dependent axial and flexural strengths of reinforced concrete sections were also suggested.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.233-238
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• 2006

In lifetime estimation, the FEM analysis method is proposed for predicting corrosion failure time of concrete structures exposed to sea-water. This study shows that the corrosion rate of rebar in artificial pore solution can be transferred to the corrosion rate of rebar in concrete using the relationship between pore volume and concrete volume by Jennings' model. And this study considered the pitting corrosion effects of reinforcement bar on corrosion failure analysis, rebar size to cover depth and nonlinear crack analysis. These analysis results have good accordance with the experimental results of Williamson's work. This methodology can be applied to lifetime prediction procedure of reinforced concrete structures and also gives more reasonable results of concrete cover failure time estimation of reinforced concrete structures exposed to sea-water.

• Journal of Environmental Science International
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• v.13 no.2
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• pp.175-180
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• 2004

A prompt gamma-ray neutron activation (PGNA) system was simulated by the Monte Carlo N-Particle transport code (MCNP-4A) to estimate the level at which the scattered photon fluence rate, the absolute efficiency of the HPGe-detector, the volume of the concrete sample and the $^{35}$ /Cl(n, ${\gamma}$) reaction rate in this sample contribute to the count rate in the NaCl concentration measurement. The n- ${\gamma}$ fluence rates at the ST-2 beam tube exit of the HANARO reactor were used as input data, and the GAMMA-X type HPGe detector was modeled to tally 1.1649 MeV ${\gamma}$ -rays emitted from the $^{35}$ Cl(n, ${\gamma}$) reaction in the concrete sample. For three cylindrical concrete samples of 13.8, 46.8 and 157.1 ㎤ volumes, respectively, the relations between the NaCl weight fractions of 0.1, 1, 2 and 5 % in each of the concrete samples and the 1.1 649 MeV pulses created in the HPGe detector model were studied. As a result, it was found that the count rate at the same NaCl concentration nearly depends on the volume of the samples in a simulated condition of the same NaCl concentration samples, and that the linearities of the NaCl concentration calibration curves were reasonable in the narrow range of the NaCl weight fraction.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.223-233
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• 2002

The air distribution duct with multiple outlets is an essential part of automotive air-conditioning system In a bus. The estimation of airflow rate in an automotive air-conditioning duct is typically very complicate due to large variations in cross-sectional area and abrupt changes in flow direction, as well as unbalanced distribution of the flow. In this paper, the flow characteristic in a duct with multiple outlets is investigated through experiment, CFD simulation and a one-dimensional simulation. Numerical simulations have been performed for two simplified air conditioning ducts with multiple outlets used in a medium bus. The three dimensional Navier-Stokes code was used to evaluate the overall pressure, velocity Held, and distribution rate at each diffuser according to the change of various design parameters such as ratio of cross-sectional area and radius of bifurcated region. In addition, a one-dimensional program based on Bernoulli equation was developed to obtain optimized diffuser area required to equalize discharge flow rate at each outlet. As a result of this study, optimized diffuser area of design variable by one-dimensional program was very reasonable as compared to the trend deduced from CFD Simulation. Therefore, the simple and convenient one-dimensional analysis developed in this study can be applied in practical design procedure for air-conditioning duct.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.1-5
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• 2000

Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. This experiment was conducted to characterize the development of soybean [Glycine max (L.) Merr.] leaf area. Plastochron index and leaf relative growth rate of Jackson was contrasted with the PI416937, which also has demonstrated tolerance to drought. First, plastochron ratio (PR) and plastochron index (PI) were evaluated in greenhouse to compare the leaf growth rate between two genotypes under well-watered condition. There was reasonable constancy of PR between two genotypes. The PR means of Jackson and PI416937 were 0.41 and 0.44, respectively. A fairly smooth increase of PI during vegetative stage was observed. Second, the relative growth rates were graphed against leaf area, normalized with respect to final leaf area, under well-watered and water-deficit conditions. Leaf growth was sustained longer in well-watered condition than water-deficit condition and there was a sizable proportion of leaves which was ceased earlier their growth in water-deficit condition compared to well-watered condition. The leaf relative growth rate of Jackson until leaves had completed at 45% of their growth during water deficit period was higher than that of PI416937.