• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.33-34
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• 2020

𝛾-dicalcium silicate (𝛾-C₂S) is characterized by its strong carbonation reactivity and has the prospect to be utilized as a building material with the added benefit of CO₂ capture. This paper aims to point out the impact of 𝛾-C₂S on the microstructure characteristics and mechanical properties of GGBFS paste, and mortar samples. The compressive strength of 𝛾-C₂S added GGBFS cement mortar is higher compared to without 𝛾-C₂S in accelerated carbonation (AC) up to 14 days of curing but once the curing duration is increased, there is no significant improvement in compressive strength. This study suggests that 𝛾-C₂S can capture the atmospheric CO₂ (mostly generated from cement and metallurgy industries) and utilized in construction.

• Steel and Composite Structures
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• v.51 no.6
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• pp.647-659
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• 2024

Given the increased interest in enhancing structural sustainability, the current study sought to apply multiobjective optimization to a footbridge with a steel-concrete composite I-girder structure. It was considered as objectives minimizing the cost for building the structure, the environmental impact assessed by CO2 emissions, and the vertical accelerations created by human-induced vibrations, with the goal of ensuring pedestrian comfort. Spans ranging from 15 to 25 meters were investigated. The resistance of the slab's concrete, the thickness of the slab, the dimensions of the welded steel I-profile, and the composite beam interaction degree were all evaluated as design variables. The optimization problem was handled using the Multiobjective Harmony Search (MOHS) metaheuristic algorithm. The optimization results were used to generate a Pareto front for each span, allowing us to assess the correlations between different objectives. By evaluating the values of design variables in relation to different levels of pedestrian comfort, it was identified optimal values that can be employed as a starting point in predimensioning of the type of structure analyzed. Based on the findings analysis, it is possible to highlight the relationship between the structure's cost and CO2 emission objectives, indicating that cost-effective solutions are also environmentally efficient. Pedestrian comfort improvement is especially feasible in smaller spans and from a medium to a maximum level of comfort, but it becomes expensive for larger spans or for increasing comfort from minimum to medium level.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.4
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• pp.458-466
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• 2012

A Dual metal gate stack cylindrical/ surrounded gate MOSFET (DMGSA CGT/SGT MOSFET) has been proposed and an analytical model has been developed to examine the impact of this structure in suppressing short channel effects and in enhancing the device performance. It is demonstrated that incorporation of gate stack along with dual metal gate architecture results in improvement in short channel immunity. It is also examined that for DMGSA CGT/SGT the minimum surface potential in the channel reduces, resulting increase in electron velocity and thereby improving the carrier transport efficiency. Furthermore, the device has been analyzed at different bias point for both single material gate stack architecture (SMGSA) and dual material gate stack architecture (DMGSA) and found that DMGSA has superior characteristics as compared to SMGSA devices. The analytical results obtained from the proposed model agree well with the simulated results obtained from 3D ATLAS Device simulator.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.1-6
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• 2004

For many years, fatigue was discounted as a potential cause of or contributor to human error. However, resent accident data and research point to fatigue as a cause of and/or contributor to human error precisely because of its impact on performance. The goal of this study is to analyze and examine of the fatigue factors related to human error. In this study, we carried out the questionnaire sw-vey which concerned with the fatigue factors.

• Journal of Distribution Science
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• v.15 no.2
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• pp.53-58
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• 2017

Purpose - The world economy is changing with FTA. Lots of FTAs are going on between countries and economic blocs in the world economy as the battle field of FTA. This study is aims to suggest a practical data about Korea-China FTA by analyzing an economic ripple effect and main issues on Korea-China FTA negotiation. Research design, data, and methodology - This study analyzes the economic impact and major issues expected during the promotion period of Korea-China FTA, and promoted the purpose of this research with literature review and comparative analysis. Result - FTA agreement with China is expected to contribute to Korean economic growth by bringing effectiveness of securing and resolving mutual trade conflict, and one-sided trade protection control of Chinese domestic demand market. The potentiality between United States and Korea is also very important issue. Conclusions - To minimize the adverse effects of FTA and to maximize the positive effects on the logistics industry, the Correspondence strategy is suggested based on the effects of FTA after analyzing the entire situation of the logistics. Especially, this article places emphasis on a close cooperation system between the government agencies to get a good conclusion from the negotiation even if the e-Commerce issue to be a critical point under Korea-China FTA.

• Journal of ILASS-Korea
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• v.6 no.3
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• pp.38-44
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• 2001

The effect of four diesel fuels with oxygenated agents fuels on spray properties from plain-orifice atomizer was investigated. The oxygenates evaluated were diglyme, MTBE, DEE and DMM and were blended in weights of 5, 10, 15, 20 and 30% in a baseline diesel fuel. The physical properties such as surface tension, density and viscosity are also measured for each blended oxygenated fuels. It was found that changes in physical properties of fuels considered are enough to influence spray properties, i.e. spray angle, spray tip penetration and mean drop size. Spray properties were measured by PMAS(particle motion analysis system) which is employing a point measurement technology. Spray angle increased with increase in oxygenate content. The effect, however, was not great in the higher blend level. The oxygenated fuels produced more shorter spray tip penetration than diesel fuels. SMD was decreased with the increase in blending percent. SMD for DMM and DEE are represented 10.33 and 3.41% decreasing rates respectively. It was found that changes in spray characteristics of oxygenated fuel were easily large enough to impact pollutant emissions. It was clear from this study that spray characteristics of oxygenated fuel is one of possible cause of reducing pollutant emissions. It was clear from this study that spray characteristics of oxygenated fuel is one of possible cause of reducing pollutant emissions from diesel engines when oxygenated fuels is applied.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.326-334
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• 2010

In this study, we provide a comprehensive review of the CIP(Constrained Interpolation Pro file/Cubic Interpolated Propagation) method with a pressure-based algorithm that is known as a general numerical solver for soled liquid, gas and plasmas. And also we introduce a body-fitted grid system(Soroban grid) for computation of strongly nonlinear marine hydrodynamic problems such as slamming water on deck, wave impact by green water. This grid system can keep the third-order accuracy in time and space with the help of the CIP method. The grid system consists of the straight lines and grid points. In the 2-dimensional grid case, each grid points moving in these lines like abacus - Soroban in Japanese. The length of each line can be different and the number of grid points in each line can be different. Mesh generation and searching of upstream departure point are very simple and possible to mesh-free treatment. To optimize computation of free-surface and multi-fluid flows, We adopt the C-CUP method. In most of the earlier computations, the C-CUP method was used with a staggered-grid approach. Here, because of the mesh free nature of the Soroban grid, we use the C-CUP method with a collocated-grid approach.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.147-153
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• 2012

As IT circumstance is complicated and the scale of infra increase, a recognition of security information system and data availability are raised. At this point, a value of information assets regards important, a study of high performance backup system for disaster recovery countermeasure is a field to impact on business directly. Therefore, this study executes duplication of high performance backup system and data consistency verification. And, a performance of comparison to DB table recovery process, a transaction process speed of duplication according to network bandwidth, and performance evaluation were executed.

• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.426-434
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• 2006

The impact of leakage was incorporated into the transfer functions of the complex head and discharge. The impedance transfer functions for the various leaking pipeline systems were also derived. Hydraulic transients could be efficiently analyzed by the developed method. The simulation of normalized pressure variation using the method of characteristics and the impulse response method shows good agreement to the condition of turbulent flow. The leak calibration could be performed by incorporation of the impulse response method with Genetic Algorithm (GA) and Harmony Search (HS). The objective functions for the leakage detection can be made using the pressure-head response at the valve, or the pressure-head or the flow response at a certain point of the pipeline located upstream from the valve. The proposed method is not constrained by the Courant number to control the numerical dissipation of the method of characteristics. The limitations associated with the discreteness of the pipeline system in the inverse transient analysis can be neglected in the proposed method.

• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.79-87
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• 2009

Residential Buildings should provide high-quality, comfortable environments to support the activities of their occupants. The indoor environment of residential buildings, which includes thermal, lighting, acoustic, and indoor air quality, has a significant impact on health and quality of life. The comfortable living environment in residential buildings result from appropriately combining these environmental quality factors, and the performance of building systems must be compatible with the activities of the occupants. The objective of this research is to investigate and analyze the relationship between physical environmental conditions and occupant responses for improving environmental quality (EQ) in apartment buildings with four different building orientations (i.e. E, W, S, N) in two different seasons (i.e. winter and summer). The occupant survey was conducted in actual apartment buildings. The Physical environmental conditions in apartment buildings differed substantially depending on space, outdoor weather conditions and building orientations. Each space within the same apartment building had different environmental conditions. Combinations of unbalanced physical environmental conditions in apartment building decrease occupants' satisfactions and their perceptions of overall residential quality. Occupants' satisfaction and their responses to physical characteristics of their residential environment is related to thermal, lighting, acoustic, and indoor air conditions in their buildings. The result from this research will help designers and researchers to identify problems and develop solutions for improving environmental quality from the occupants' point of view.