• Environmental Engineering Research
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• v.17 no.1
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• pp.27-34
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• 2012

This paper deals with the evaluation of environmental impact of rail and road transport in South Korea. A framework of energy input-output analysis is employed to estimate the total energy consumption and $CO_2$ emission in acquiring and using a life cycle of passenger and freight transport activity. The reliability of $CO_2$ emission based on uncertainty values is assessed by means of a Monte Carlo simulation. The results show that on a passenger-kilometers basis, passenger roads have life cycle emissions about 1.5 times those of rail, while that ratio is ten times greater when the scope of evaluation regards the tailpipe. In the case of freight transport, on a million ton-kilometers basis, the value for road mode is estimated to be about three times compared to those of rail mode. The results also show that the main contribution of $CO_2$ emission for road transport is the operation stage, accounting for 70%; however, the main contribution for rail transport is the construction and supply chain stage, accounting for over 50% emission.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1561-1567
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• 2017

This paper calculates the effective capacity of EES providing the primary frequency control service based on its contribution to the frequency response of the power system. The amount of governor response from conventional generators which can be replaced by the primary frequency control from EES keeping the frequency response of the power system is defined as the effective capacity. The proposed method for calculating the effective capacity of EES is verified through case studies employing Korean power system. Furthermore, the application of the effective capacity of EES to power system operation is also discussed.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.162-168
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• 2011

Many ligands have been experimentally designed and tested for their activities as inhibitors against bacterial enoyl-ACP reductase (FabI), ENR. Here the binding energies of the reported ligands with the E. coli ENR-$NAD^+$ were calculated, analyzed and compared, and their molecular dynamics (MD) simulation study was performed. IDN, ZAM and AYM ligands were calculated to have larger binding energies than TCL and IDN has the largest binding energy among the considered ligands (TCL, S54, E26, ZAM, AYM and IDN). The contribution of residues to the ligand binding energy is larger in E. coli ENR-NAD+-IDN than in E. coli ENR-$NAD^+$-TCL, while the contribution of $NAD^+$ is smaller for IDN than for TCL. The large-size ligands having considerable interactions with residues and $NAD^+$ have many effective functional groups such as aromatic $\pi$ rings, acidic hydroxyl groups, and polarizable amide carbonyl groups in common. The cation-$\pi$ interactions have large binding energies, positively charged residues strongly interact with polarisable amide carbonyl group, and the acidic phenoxyl group has strong H-bond interactions. The residues which have strong interactions with the ligands in common are Y146, Y156, M159 and K163. This study of the reported inhibitor candidates is expected to assist the design of feasible ENR inhibitors.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.386-396
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• 2022

To analyze the influence of variables of roadheaders, the linear cutting testing data of pick cutter were collected from the former literatures. The input factors were set up as uniaxial compressive strength, cutting depth, cutting spacing, attack angle, skew angle, and output factors were determined as specific energy, average cutting force, maximum cutting force, average vertical force, and maximum vertical force. After composing a table of the design of experiment (DOE). The contribution level of each factor was calculated by analysis of variance (ANOVA). As a result, the factors having greatest influence on cutting force and specific energy were uniaxial compressive strength and cutting spacing.

• Asia Pacific Journal of Business Review
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• v.2 no.1
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• pp.21-52
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• 2017

Nowadays every technology is becoming smarter. Consequently, intensive use of ICT in the whole industries and cities enables a sustainable approach to meet enormous productivity, efficiency, transparency and conservation of natural recourses. Likewise, the role of ICT in terms of controlling, monitoring in the energy industry allows integrating potential renewables, bulk energy conservation and reliable optimized operation in the entire system. In this paper outlines challenging issues in renewable energy integration in Mongolia and proposes potential recommendations and conclusions. The author investigated the main technologies used in energy industry mainly smart grid, challenges and policy aspect in Mongolian energy sector by using the primary and secondary approach with case studies and literature based methodologies. Based on the policy aspect and current implementation of smart grid, the paper tries to address the readiness for the main application and future potential ICT driven applications. Furthermore, it concluded that ICT convergence is demanded to overcome the current vulnerabilities and significant momentum to leave behind by using its potential energy recourses and favorable geographical state. Policymakers may find this study useful, as it answers the question of whether ICT investment can ultimately reduce energy consumption and may aid in future planning. Even tough, in order to develop a smart grid and integrating renewables firstly set an appropriate market structure, ICT will key enabler to make energy system more profitable and sustainable. Regarding the result of this study, ICT deployment contribution is a huge demand for future opportunities energy in Mongolia.

• Korean System Dynamics Review
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• v.7 no.2
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• pp.57-80
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• 2006

Nuclear technology made a great contribution to the national economy and society by localization of nuclear power plant design, and by stabilization of electricity price, etc. It is very important to conduct the retrospective analysis for the nuclear technology contribution to the national economy and society, but it is more important to conduct prospective analysis for the nuclear technology contribution. The term "technology value" is often used in the prospective analysis to value the result of technology development. There are various definitions of technology value, but generally it means the increment of future revenue or the reduction of future cost by technology development. These technology valuation methods are widely used in various fields (information technology or energy technology, etc). The main objective of this research is to develop valuation methodology that represents unique characteristics of nuclear power technology. The valuation methodology that incorporates market share changes of generation technologies was developed. The technology valuation model which consists of five modules (electricity demand forecast module, technology development module, market share module, electricity generation module, total cost module) to incorporate market share changes of generation technologies was developed. The nuclear power technology value assessed by this technology valuation model was 3 times more than the value assessed by the conventional method. So it was confirmed that it is very important to incorporates market share changes of generation technologies. The valuation results of nuclear power technology in this study can be used as policy data for ensuring the benefits of nuclear power R&D (Research and Development) investment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.7
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• pp.625-638
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• 2014

In this study, the uncertainties in the critical flow functions (CFFs) calculated by the AGA8-dc equation of state were estimated. To this end, the formulas for enthalpy, entropy, and speed of sound, which are used in calculating the CFF, were expressed in the form of dimensionless Helmholtz free energy and its derivatives, and the uncertainty in Helmholtz free energy was inferred. To consider the variations in the compressibility-dependent variables induced by the variation (i.e., uncertainty) in compressibility, the form of the AGA8-dc equation was modified to have a deviation equal to the uncertainty under each flow condition. For each independent uncertainty component of the CFF, a model for uncertainty contribution was developed. All these changes were applied to GASSOLVER, which is KOGAS's thermodynamic database. As a result, the uncertainties in the CFF were estimated to be 0.025, 0.055, and 0.112 % at 10, 50, and 100 bar, respectively, and are seen to increase with the increase in pressure. Furthermore, these results could explain the deviations in the CFFs across the different labs in which the CFF international comparison test was conducted under the ISO management in 1999.

• Korean Journal of Community Nutrition
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• v.18 no.2
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• pp.134-141
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• 2013

This study was conducted to investigate instant coffee-mix intakes and its relations with anthropometric measurements, nutrient intake, and blood lipid in Gangneung and Samcheok residents. Coffee-mix is a mixture of instant coffee, sugar and coffee-creamer. It is a standardized convenience food in Korea. Recently, Koreans appear to consume too much of instant coffee-mix. The respondents of this study were 218 Koreans (Gangneung region 133, Samcheok region 85). The average age was 56.0 years (male), 57.5 years (female). They were divided into 2 groups, the instant coffee-mix drinkers and the non-drinkers. The nutrient intake and anthropometric measurements and their relations with coffee-mix intakes were analyzed (nutrient intakes were calculated by converting per 1,000 kcal and adjusted by age, region). As for male, body fat was significantly higher in coffee-mix drinkers (18.1 kg, 25.0%) than in non-drinkers (17.1 kg, 23.8%). In the case of females, serum triglyceride was significantly higher in coffee-mix drinkers (109.1 mg/dL) than in nondrinkers (102.9 mg/dL). Coffee-mix intakes and coffee-mix's contributions to energy were higher for participants from Samcheok (21.2 g, 4.7%) than those from Gangneung (16.6 g, 3.4%). In addition, for Samcheok, coffee-mix's contribution to energy was significantly higher in male (5.6%) than in female (4.2%). Coffee-mix intakes and energy contribution of coffee-mix were not significantly correlated with anthropometric measurements. Only HDL-cholestrol showed significantly negative correlation with coffee-mix's contributions to energy. Based on the above results, we conclude that usual instant coffee-mix intake may increase intakes of sugar and fat and exert negative effects on serum lipids. Therefore, it is needed to control too much instant coffee-mix intake in the dietary management of rural residents.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1633-1637
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• 2019

While considering the photon attenuation coefficient (${\mu}$) and its related parameters for photons shielding, it is necessary to account for its transmitted and reflected photons energy spectra and dose contribution. Monte Carlo simulation was used to study the efficiency of clay ($1.99g\;cm^{-3}$) as a shielding material below 150 keV photon. Am-241 gamma source and an X-ray of 150 kVp were calculated. The calculated value of ${\mu}$ for Am-241 is higher within 5.61% compared to theoretical value for a single-energy photon. The calculated half-value layer (HVL) is 0.9335 cm, which is lower than that of ordinary concrete for X-ray of 150 kVp. A thickness of 2 cm clay was adequate to attenuate 90% and 85% of the incident photons from Am-241 and X-ray of 150 kVp, respectively. The same thickness of 2 cm could shield the gamma source dose rate of Am-241 (1 MBq) down to $0.0528{\mu}Sv/hr$. For X-ray of 150 kVp, photons below 60 keV were significantly decreased with 2 cm clay and a dose rate reduction by ~80%. The contribution of reflected photons and dose from the clay is negligible for both sources.

• Earthquakes and Structures
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• v.18 no.2
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• pp.263-273
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• 2020

The use of energy concepts in seismic analysis and design of structures requires the understanding of the input energy response of multi-degree-of-freedom (MDOF) systems subjected to strong ground motions. For design purposes and non-time consuming analysis, however, it would be beneficial to associate the input energy response of MDOF systems with those of single-degree-of-freedom (SDOF) systems. In this paper, the theoretical formulation of energy input to MDOF systems is developed on the basis that only a particular portion of the total mass distributed among floor levels is effective in the nth-mode response. The input energy response histories of several reinforced concrete frames subjected to a set of eleven horizontal acceleration histories selected from actual recorded events and scaled in time domain are obtained. The contribution of the fundamental mode to the total input energy response of MDOF frames is demonstrated both graphically and numerically. The input energy of the fundamental mode is found to be a good indicator of the total energy input to two-dimensional regular MDOF structures. The numerical results computed by the proposed formulation are verified with relative input energy time histories directly computed from linear time history analysis. Finally, the elastic input energies are compared with those computed from time history analysis of nonlinear MDOF systems.