• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.13-23
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• 2000

In this study, an flexural test on half-scale spliced PSC-I girder was conducted to verify the efficiency of the long span spliced girder as suggested by the Korean Highway Design Specification. The experimental results showed that the specimens developed a complex failure mode due to flexural-compression and torsional stress. The cracking moment of each girder was higher the experiment than was calulated by the ACI and the ultimate strength were the almost same. To estimate the safety and the structural efficiency of the spliced girder, the proposed Yielding Resistance Index(YRI) and ductility index by American Concrete Institutes were used based on the energy concept. The proposed YRI defined the ratio of crack resisting energy and the total energy calculated from load-displacement relationship. Based on the analysis of YRI and ductility index, the flexural behavior of the spliced girder was found to be efficient. Through the experimental results, the structural behavior of proposed spliced PSC I-type girder for long span bridge was found to be more efficient than the exsisting PSC I-type girders.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.576-582
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• 2016

To cope with international regulations, such as Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and so forth, and to enforce limitations on $CO_2$ emissions, green-ship technology to lower fuel consumption has been actively researched, and the development of an energy-saving device (ESD) is being pursued. In order to design an ESD for small and medium-sized domestic vessels, an analysis on flow characteristics has been performed in the present study. Through a model test and numerical analyses, the characteristics of flow around the stern bilge and bulb have been compared to improve wake quality and resistance performance. As a result of these comparisons and analyses, a vertical plate has been adopted,, as a new ESD. Design criteria for the proposed ESD are also suggested. By applying this new ESD, it is expected that the total resistance and average nominal wake can be reduced by 3.04 % and 18.8 %, respectively.

• KIEAE Journal
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• v.13 no.4
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• pp.49-54
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• 2013

released by IEA, 2010, indicated that Korea's GDP, of 8 countries surveyed-Korea, Frans, Germany, Italy, Japan, the UK, the USA, and Australia-was the lowest, but the electric consumption per head was third, following America and Australia. Thus, our government has been striving to reduce energy usage and especially to lessen the energy used in buildings, proposing a variety of road maps such as 'building energy efficiency rating' and 'energy saving design standards of buildings'. Accordingly, this study investigated the effect of the items of machine part among EPI items on the energy saving rate. I measured energy usage by ECO2 program, for simulation program, that is used for the building energy efficiency rating. Result showed that items concerning control of pumps and fans had much more saving rate than the ones concerning efficiency of heater and cooler that had bigger scores assigned among EPI items. Result showed that items concerning control of pumps and fans had much more saving rate than the ones concerning efficiency of heater and cooler that had bigger scores assigned among EPI items. Therefore, I think that grades assigned to items in energy performance index need to be corrected.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.500-507
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• 2010

Regard to the global warming, the shipping industries are progressed the dedicated endeavor to reduce greenhouse gas. As the study results of 2009 GHG study team, the $CO_2$ emission of shipping industries exceeded slightly 1.0 billion ton during one year(2007) and it is 3.3% of total $CO_2$ amount exhausted from all industries. This paper are introduced the energy efficiency design index / operation indicator monitoring system(EDiMS) which matched with EVAMOS software released by the dynamics laboratory of Mokpo maritime university. EDiMS can continuously be monitored amounts of $CO_2$, NOx, SOx, and PM emitted from ship and it can be applied as the useful tool of the inventory work of air pollution and the ship energy management plan for the mitigation or reduction of ship emission.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.471-477
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• 2015

When a ship sails in a seaway, the resistance on a ship increases due to incident waves and winds. The magnitude of added resistance amounts to about 15–30% of a calm-water resistance. An accurate prediction of added resistance in waves, therefore, is essential to evaluate the performance of a ship in a real sea state and to design an optimum hull form from the viewpoint of the International Maritime Organization (IMO) regulations such as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI). The present study considers added resistance problem of AFRAMAX-class tankers with the conventional bow and Ax-bow shapes. Added resistance due to waves is successfully calculated using 1) a three-dimensional time-domain seakeeping computations based on a Rankine panel method (three-dimensional panel) and 2) a commercial CFD program (STAR-CCM+). In the hydrodynamic computations of a three-dimensional panel method, geometric nonlinearity is accounted for in Froude-Krylov and restoring forces using simple wave corrections over exact wet hull surface of the tankers. Furthermore, a CFD program is applied by performing fully nonlinear computation without using an analytical formula for added resistance or empirical values for the viscous effect. Numerical computations are validated through four degree-of-freedom model-scale seakeeping experiments in regular head waves at the deep towing tank of Hyundai Heavy Industries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.274-277
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• 1996

This paper describes the realization of the full-color to the degree of nearest white light by compounding high brightness Red, Green and Blue LEDs with appropriate proportional index. Once these three colors; red, green and blue are mixed, they are genearlly additive mixing and produce white light color contrasted to negative mixing. The luminous efficiency is defined as the product of the efficiency(lm/w), which indicates the degree of perceptual response by the human eye to unit energy(W) of light emitted by an active display devises and as the conversion efficiency of the device from electric power consumed to optical energy produced. We will deduce the each number of LEDs theoretically and design several shapes of LED displays for the full-color. Finally theoretical predictions will be compared with the measured data with different type of display designs.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.4
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• pp.352-360
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• 2019

International Maritime Organization (IMO) regulates an emission of greenhouse gases by creating an Energy Efficiency Design Index (EEDI) to reduce environmental pollution. In propulsion system field, studies are under way on Energy Saving Device (ESD), which can improve propulsion efficiency with the propeller, to reduce the EEDI. Among the studies, the study of Pre-Swirl Stator (PSS) has been actively conducted from long time ago. Recently the variable pith angle type pre-swirl stator has been studied to improve the propulsion efficiency in non-uniform flow fields of the Stern. However, for traditional design methods, no specific design method has been established on the blade or location of radius. In this study, proper design method is proposed for each blade or location for radius according to hydrodynamic pitch angle.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.520-533
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• 2021

It is necessary to increase the blasting efficiency in order to minimize the economic loss caused when the excavation cross section is reduced due to the stability problem of underground mining development, and for this, a new blasting design is proposed. In this study, the blasting efficiency of the general design in the field, the suggestion designI, which added two columns to production blasting, and the suggestion design II, which added one column to create asymmetry, is compared. Advance rate and fragmentation were selected as the evaluation index of the blasting efficiency. In the case of advance rate, compared to the normal, the suggestionI improved by 6.07% and the suggestionII improved by 4.65%. In the case of fragmentation, based on P80, compared to the normal, the suggestionI reduced about 58% and the suggestionII was about 47%. Accoording to the evaluation index, the suggestion designI shows better blasting efficiency than the suggestion designII. But considering the additional work time and cost required for the suggestion designI due to the insignificant difference in the evaluation index results, the asymmetry V-cut, the suggestion designII, is judged to be a more suitable blasting design for the site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.395-402
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• 2016

This paper presents a design methodology for improving the energy efficiency by considering the inertial properties of serial manipulators. This method employed is to put the inertia matrix, which has a critical effect on the equation of motion, into the constraints of the optimization problem. Through the optimization process, we propose a design algorithm that can double-check whether the optimized parameters satisfy the required performance or not by using an auxiliary index associated with the inertia and energy. Using this design algorithm, we were able to improve the energy efficiency by minimizing the torque. We applied this method to a 3 degrees of freedom serial manipulator and simulated it.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.39-40
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• 2011

The 62nd session of the MARINE Environment Protection Committee was held in London from 11 to 15 July 2011. Mandatory measures to reduce emissions of greenhouse gases (GHGs) from international shipping were adopted at the Committee. The amendment to MARPOL Annex VI includes a new chapter 4 to make mandatory the Energy Efficiency Design Index (EEDI) for new ships and the Ship Energy Efficiency Management Plan (SEEMP) for all ships. This first mandatory measures on energy efficiency will enter into force on 1 January 2013. This amendment to MARPOL Annex VI will significantly influences the vast majority of the international maritime community. This paper mainly discusses the main results of MEPC 62nd session including the recent Emission Control Area.