• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.29-34
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• 2008

The Korean society has been changed to the aging one. The number of elderly people has been in creasing rapidly. For their social and economic activity, more convenient transport services have to be offered. Specifically, increasing mobility is one of the most urgent policies for them. One action of the policy in Seoul has introduced low floor buses since 2003. This paper shows how low floor buses affect on passengers' boarding and alighting time through the field survey. In the analysis of the survey results it has been found that the low floor buses can reduce average boarding time by 0.8 sec, especially, by 1.1 sec (about 36%) for elderly passengers. These outcomes expect total bus operating hours as well as headways could be reduced, and operating cost and passengers' waiting time could be saved.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.570-574
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• 2008

The 'gate non-stop system utilizing RFID (900MHz)', which is the core of this research, is the system which connects RFID to recognize the vehicle information without stopping when a vehicle (trailer) passes a gate to carry in or out containers in a terminal and automatically provides the container information provided by the terminal for the RFLDU device installed in the vehicle.In order to design and implement this, the RFID technical section uses a UHF band (900MHz) RFID tag and a reader and implements a RFID middleware and an application program for smooth data collection and execution (operation). In addition, the system stability was verified through experiments and operations of the system implemented in this research at real harbors/quays, and based on the verified result, the maximization of vehicle (trailer) and terminal productivity and the reduction of distribution cost are expected.

• International Journal of Concrete Structures and Materials
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• v.11 no.2
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• pp.199-213
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• 2017

Chloride penetration is among the main causes of corrosion initiation in reinforced concrete (RC) structures producing premature degradations. Weather and exposure conditions directly affect chloride ingress mechanisms and therefore the operational service life and safety of RC structures. Consequently, comprehensive chloride ingress models are useful tools to estimate corrosion initiation risks and minimize maintenance costs for RC structures placed under chloride-contaminated environments. This paper first presents a coupled thermo-hydro-chemical model for predicting chloride penetration into concrete that accounts for realistic weather conditions. This complete numerical model takes into account multiple factors affecting chloride ingress such as diffusion, convection, chloride binding, ionic interaction, and concrete aging. Since the complete model could be computationally expensive for long-term assessment, this study also proposes model simplifications in order to reduce the computational cost. Long-term chloride assessments of complete and reduced models are compared for three locations in France (Brest, Strasbourg and Nice) characterized by different weather and exposure conditions (tidal zone, de-icing salts and salt spray). The comparative study indicates that the reduced model is computationally efficient and accurate for long-term chloride ingress modeling in comparison to the complete one. Given that long-term assessment requires larger climate databases, this research also studies how climate models may affect chloride ingress assessment. The results indicate that the selection of climate models as well as the considered training periods introduce significant errors for mid- and long- term chloride ingress assessment.

• Land and Housing Review
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• v.14 no.2
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• pp.97-107
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• 2023

This study examined how to better provide quality temporary housing for people in the event of natural and social disasters. Design for Manufacture and Assembly (DfMA) is suitable for creating an efficient planning model for the mass production and transport of a modular house. The proposed DfMA model has the following three characteristics. First is the division of the modular house into service modules and functional modules and to create diversity by developing standard parts and multi-functional parts. Second is a flexible layout suitable for various site conditions. Such flexible layouts would allow identical homes to be mass produced and deployed to a variety of locations, both nationally and internationally. Third is to simplify and minimize the automation process with dry construction to increase production efficiency. Application of this DfMA design method can lead to reduced construction time and cost and improve housing quality.

• Spatial Information Research
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• v.20 no.4
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• pp.29-36
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• 2012

The low-carbon freight transportation system was introduced due to increase traffic congestion cost and carbon-dioxide for global climate change according to expanding city logistics demands. It is necessary to create 3D-based road network map for representing realistic road geometry with consideration of fuel consumption and carbon emissions. This study propose that 3D road network model expressed to realistic topography and road structure within trunk road for intercity freight through overlaying 2D-based transport-related thematic map and 1m-resolution DEM. The 3D-based road network map for the experimental road sections(Pyeongtaek harbor-Uiwang IC) was verified by GPS/INS survey and fuel consumption simulation. The results corresponded to effectively reflect realistic road geometry (RMSE=0.87m) except some complex structure such as overpass, and also actual fuel consumption. We expect that Green-based freight route planning and navigation system reflected on 3D geometry of complex road structure will be developed for effectively resolving energy and environmental problems.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.402-409
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• 2013

In metropolitan railway systems, the average commuting time keeps increasing as the scheduled speed increases, and this leads to a decline of rail service usage and competitiveness. Therefore, effective express operation for urban trains is required to improve the scheduled speed. In this study, based on the obtainable time shortening efficiency and economic viability, several express operations are suggested for urban railways and these suggestions are compared by considering high performance trains with acceleration/deceleration and maximum speed improvement. As a result, the optimum express system, which can minimize the cost for sidetrack construction, is suggested.

• Journal of Korea Port Economic Association
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• v.23 no.1
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• pp.61-73
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• 2007

Creating more efficient and effective intermodal transportation service in Northeast range is a critical issue because of more increased trade volume & demand for intermodal service in the world market and geographical barriers associated with goods transportation, especially in Korea, China and Japan. This study examines the possibility of Rail-ferry introduction and possible route in Northest area which can provide each country mutual economical and logistical satisfaction. But, this study requires more empirical and concrete examination based on the cost & benefit analysis.

• Membrane Journal
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• v.26 no.2
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• pp.146-151
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• 2016

Sulfonated poly (arylene ether sulfone) (SPAES) random copolymers have merits such as high proton conductivity, relatively low production cost, and thermochemical resistance when applied as polymer electrolyte membranes for fuel cells. However, it is difficult to directly employ SPAES copolymers into practical fuel cell membrane applications owing to their low chemical stability and dimensional instability under harsh operation conditions. A plausible solution is to impregnate SPAES copolymers into support films (e.g., electrospun polyimide support) with interconnected pore structures and high thermochemical toughness. In this study, a SPAES copolymer with a swivel group, which induces high free volume for fast ion transport, is chosen as ionomers to prepare pore-filling membranes (PFMs). The feasibility of the resulting membranes is evaluated via membrane characterizations.

• Journal of the Korean GEO-environmental Society
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• v.23 no.12
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• pp.41-53
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• 2022

After industrialization has been started, mankind needs and consumes more resources. Now, the resources depletion is a serious problem in the Earth. However, there are infinite resources in the Space. Especially, the Moon is the closest planet and has much resources, including Helium-3 and rare earths, which are needed to human being in the future. Humanity needs to reside on the moon to harvest these resources. For the resident, much resources, such as food, construction, and industrial materials, are needed. However, to transport these resources to the Moon from the Earth, an astronomical cost should be consumed. Thus, research is underway to support human activities by procuring resources locally. This is called In-Situ Resources Utilization (ISRU), which is the essential technology for the space development. In this paper, the reason why ISRU is essential and the its status are introduced and future research projects will be explained.

• Korean Journal of Construction Engineering and Management
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• v.24 no.6
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• pp.24-35
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• 2023

Recently, the Ministry of Land, Infrastructure and Transport presented the '6th Construction Technology Promotion Basic Plan' and 'Smart Construction Revitalization Plan (2022.7.20)'. Off-Site Construction (OSC), which involves construction and production of PC (Precast Concrete) and Modular, etc., has advantages in shortening the construction period, reducing costs, improving quality, reducing construction waste, and reducing safety accidents. However, the construction cost is high compared to the traditional RC construction method, which has hindered its utilization and spread. In this study, OSC utilization was improved. An economic analysis indicator and methodology that can support decision-making in the planning and design stages for multi-unit housing were proposed. The factors used in the economic analysis of OSC (based on the PC method) of apartment houses were reviewed. As for the indicators used in the cost and benefit section, 'Construction Period', 'Disaster Occurrence', 'Waste Generation', and 'Greenhouse gas Emission', which reflect the technical advantages of OSC, were derived. In addition, a scenario analysis was conducted based on actual apartment housing case data for the presented economic analysis indicators and benefit calculation standards. The level of benefit that offsets the difference between the existing RC construction method and the construction cost was reviewed. In future studies, it will be necessary to conduct additional case studies to apply the measurement criteria for detailed indicators and supplement the benefit indicators.