• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.434-446
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• 2017

This study was carried out to suggest new indicators to be used at airports. Generally, passengers and cargo will be handled at the airport, and the airport will achieve revenues through them. However, all airports can not have the same distribution of passenger and cargo throughput. When comparing and analyzing several airports, a uniform result can be expected only if a unit airport throughput indicator is applied. The 'Work Load Unit' is an indicator that integrates passengers and cargo into one, and assumes that the value of one passenger is equivalent to the cargo volume of 100kg. The existing WLU was set up based on the experience at the airport rather than being established through reasonable grounds or analysis, so there was a lot of controversy. The purpose of this study is to overcome these limitations and to suggest new index. In this study, we applied a method to compare the relative value of cargo and passenger to airport revenue. In order to analyze cargo value and passenger value, airport revenues are classified into aircraft operation related revenues, passenger handling related revenues, and commercial revenues. A total of 50 airports were selected, including 14 airports in Asia, 18 airports in Europe and 18 airports in North America. According to the final analysis results, it is concluded that the cargo is equivalent to 280kg of cargo based on the contribution of one passenger averagely. This is higher than the value of 100Kg cargo per passenger.

• Tribology and Lubricants
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• v.15 no.1
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• pp.17-23
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• 1999

A Gerotor hydraulic motor is a planar mechanism consisting of a pair of rotors one of which encloses another rotor. The motion of the inner-rotor relative to the outer-rotor is produced by the pressure difference between the adjacent chambers. A design method of inner-rotor tooth profile using unit tangential vectors is presented in this work. Based on the relationships derived, the influence of the eccentricity of inner-rotor and the radius of circular arc tooth on the flow rate, torque and curvatures were investigated. It was shown that the flow rate and mean torque is proportional to eccentricity, but inversely proportional to the radius of circular arc teeth. Also, the maximum value of the equivalent curvature is increased as the eccentricity and the radius of circular arc teeth increased.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.153-161
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• 2009

Three-dimensional finite-element methods(FEM) have been used to analyze the thermal stress of an exhaust gas recirculation(EGR) cooler due to thermal and pressure load. Since efficiency and capability of the heat exchanger are mainly dependent on net heat transferring area of the EGR cooler system, the tube inside the system has a numerous dimples on the surface. Thus for finite element analysis, firstly the dimple-typed tube is modeled as a plain element without the dimple, and then the equivalent thermal conductivities and elastic modulus are calculated. This work describes the numerical homogenization procedure of the dimple-typed tube and verifies the equivalent material properties by comparison of a single unit and the actual full model. Finally, the homogenization scheme presented in this study can be efficiently applied to finite element analyses for the thermal stress and deformation behavior of the EGR cooler system with the dimple-typed tube.

• Advances in Computational Design
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• v.1 no.2
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• pp.139-154
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• 2016

The usage of sandwich structure is extensively increasing in lightweight protective structures due to its low density and other useful properties. Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections by comparing to an equivalent monolithic plate of same metal and similar mass per unit density. However, the process of localized impact on solid structures involving plastic deformation, high strain rates, temperature effect, material erosion, etc. does not hold effectively as that of monolithic plate. In present work, the applications of the sandwich plate with corrugated core have been extended to develop optimized lightweight armour using foam as medium of its core by explicit finite element analysis (FEA). The mechanisms of hardened steel projectile penetration of aluminum corrugated sandwich panels filled with foams have been numerically investigated by finite element analysis (FEA). A comparative study is done for the triangular corrugated sandwich plate filled with polymeric foam and metallic foam with different densities in order to achieve the optimum penetration resistance to ballistic impact. Corrugated sandwich plates filled with metallic foams are found to be superior when compared to the polymeric one. The optimized results are then compared with that of equivalent solid and unfilled cores structure to observe the effectiveness of foam-filled corrugated sandwich plate which provides an effective resistance to ballistic response. The novel structure can be the alternative to solid aluminum plate in the applications of light weight protection system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.95-100
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• 2004

본 논문은 도로 건설 공사 프로젝트들의 전 공정에 걸쳐 수행되는 모든 작업들을 대상으로 총 프로젝트 생산성 (Total Project Productivity)을 측정하고 분석하기 위한 방법을 소개한다. 측정 방법의 주안점은 복합적으로 병행되는 작업들의 생산량을 통합하여, 프로젝트 전체에 대한 포괄적인 생산성 값들을 구하는 방법을 개발하는데 두고 있다. 이 방법을 통해 Florida Department of Transportation (FDOT)로부터 발주된 세 개의 실제 고속도로 건설 공사 프로젝트들로부터 수천 개의 총 프로젝트 생산성 데이터 값들이 얻어졌으며. 이를 바탕으로 프로젝트 생산성을 분석하기 위한 방법의 타당성 검증이 이루어졌다. 그 결과로, 프로젝트 레벨에서의 총 생산성은 건설 작업들에 관한 현장 자료를 바탕으로 측정과 분석이 이루어질 수 있음이 입증되었다.

• Journal of the Society of Disaster Information
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• v.2 no.1
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• pp.129-137
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• 2006

The present work is attempt to evaluate the temperature dependence of blast furnace slag concrete(BFSC) based on the concrete strength cured with different curing temperatures and ages. A equivalent substitution index(ESI) was induced to explain temperature dependence of concrete quantitatively as well as concrete strength. The results from compressive strength showed substantial crossover effect. which is the phenomenon that the compressive strength cured at low temperature becomes stronger than the one cured at high temperature. The crossover effect found more definitely on BFSC than plain concrete.. The ESI became 1.1 and 1.0 for the BFSC cured at $20^{\circ}C$ and $30^{\circ}C$ after age of 56 days, respectively. Which means that the contribution to strength development of blast furnace slag per unit mass is stronger than that of the Portland cement. It was considered therefore that the optimum curing temperature for BFSC is $20^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.1-5
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• 2000

As the semiconductor devices are miniaturized, the number of the unit cleaning processes increases. In order to processes by conventional RCA cleaning process, the consumption of volume of liquid chemical and DI water became huge. Therefore, the problem of environmental issues are evolved by the increased consumption of chemicals. To resolve this matter, an advanced cleaning process by Electrolyzed Water was studied in this work. The electrolyzed water was made by an electrolysis equipment which was composed of three chambers of anode, cathode, and middle chambers. In the case of electrolyzed water with electrolytes in the middle chamber, oxidatively acidic water of anode and reductively alkaline water of cathode were obtained. The oxidation/reduction potentials and pH of anode water and cathode water were measured to be +l000mV and 4.8, and -530mV and 6.3, respectively. The Si-wafers contaminated with metallic impurities were cleaning with the electrolyzed water. To analysis the amounts of metallic impurities on Si-water surfaces, ICP-MS(Inductively Coupled Plasma-Mass spectrometer) was introduced. From results of ICP-MS measurements, it was concluded that the ability of electrolyzed water was equivalent to that of the conventional RCA cleaning.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.207-208
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• 2023

The procedure of predicting the construction cost and selecting the best alternative is performed based on comparative review of each building case. In the case of office building, it is required continuously until design is complete, since the owner requirements are various and likely to change during the design process compared to a standardized apartment. However, since the comparison work for each alternative in practice uses only the unit construction cost, there is no correlation between the alternative and the final result, and it is difficult to quantitatively determine the effect of the determined design factor on the total construction cost. It is needed that a means to support the generation of design alternatives using similar building cases during the design phase. This paper proposes a BIM-based data replacing process to support creating and comparison of design alternatives of internal finishing for office building. When design alternatives are created through the proposed process, it is possible to compare several similar cases with current project under equivalent design circumstance. Because only some finishing properties are replaced while maintaining the shape information such as the length, height, and base constraint of the object to be replaced.

• Structural Monitoring and Maintenance
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• v.2 no.4
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• pp.319-338
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• 2015

The electro-mechanical impedance (EMI) technique makes use of surface-bonded lead zirconate titanate (PZT) patches as impedance transducers measuring impedance variations monitored on host structural components. The present experimental work further evaluate an alternative to the conventional EMI technique which performs measurements of the variations in the output voltage of PZT transducers rather than computing electromechanical impedance (or admittance) itself. This paper further evaluates a variant of the EMI approach presented in a previous work of the present authors, suitable, for low-cost concrete structures monitoring applications making use of a credit card-sized Raspberry Pi single board computer as core hardware unit. This monitoring approach is also deployed by introducing a new damage identification index based on the ratio between the area of the 2-D error ellipse of specific probability of EMI-based measurements containment over that of the 2-D error circle of equivalent probability. Experimental results of damages occurring in concrete cubic and beam specimens are investigated under increasing loading conditions. Results illustrate that the proposed technique is an efficient approach for identification and early detection of damage in concrete structures.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.121-124
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• 2002

This work was initiated to develope a recombinant oral poliovaccine (OPV), which is highly advanced in safety (minimizing VAPP) by introducing Type 2,3 poliovirus epitopes into our RPS-Vax system. We have introduced several potential vaccine epitopes of poliovirus Type 2, and 3 into RPS-Vax system, resulting in production of recombinant polioviruses. Any of these chimeric viruses, however, were not detected for their foreign gene expression by serotype-specific mouse antiserum. We have designed several folding units to stabilize the introduced vaccine protein and attached short epitope-concatamer or epitope-multimer to them, followed by production of chimeric viruses. Only those who have an HIV-1 Tat-mediated folding unit were nicely detected for the introduced foreign proteins by anti-Tat antiserum and type-specific peptide-induced antisera. Nevertheless, introduced epitopes were not detected in Western blot experiment with each serotype-specific antiserum. None of the mice inoculated with these chimeric viruses showed preventative immunity when challenged with Lansing and Leon wildtype 2 and 3 poliovirus, and the antiserum did not show neutralizing capacity in vitro. Conformational epitope covering B/C loop region of type 2 and 3 were newly designed by computer modeling, and introduced into the RPS-Vax vector system, followed by production of chimeric viruses. Introduced epitope regions were nicely detected by anti-Tag23 mAb or peptide antibody, but still not detected by poliovirus antiserum. Nevertheless, neutralizing antibody was detected in the Tg-PVR mice even when inoculated once with these chimeric viruses. Also, the immunized mice showed perfect preventative immunity against the wild Type poliovirus Lancing or Leon. When boosted appropriately, those chimeric virus-inoculated Tg-PVR mice produced equivalent amounts of neutralizing antibody to those in Sabin 2/3-immunized mice. These data strongly suggest that our recombinant poliovirus (RPS-PV2 and RPS-PV3) can be used as a safe and effective rec-OPV instead of any preexisting poliovaccine.