• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.962-974
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• 2010

Recently, the convergence of information technology with bio-technology, nano-technology or other technologies has been creating a new paradigm. In a field of transportation, the intelligent transport systems which is a convergence of intelligent technologies and transportation systems have been studied. The Variable Speed Limit(VSL), is one of ITS technologies, is thought to improve safety and efficiency of transportation while controlling speed limit based on road conditions. Legacy studies have considered only one station for VSL algorithm. However, it is not appropriate for an urban freeway installed with many stations. In this paper, new algorithm is proposed to not only enhance effectiveness of VSL based on cooperation of stations but also reflect road conditions within 30 seconds. The proposed algorithm consists of 4 steps: the first is a "searching bottleneck station" step, the second is a "calculating a size of congestion" step, the third is a "calculating the number of controlled stations" step, the final is a "calculating VSL" step. This algorithm guarantees improved safety and minimum additional travel time. The travel time should be considered because drivers would against the VSL algorithm when the proposed algorithm occurs additional travel time. In our experiments, microscopic traffic simulator VISSIM is selected to perform a modeling work. The results show that proposed algorithm provides the improved safety and minimum increase of travel time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.85-94
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• 2016

Lane Designation is defined as reasonable road management to ensure the road safety and enhance road efficiency. While the lane designation system was abolished in 1999, it was redefined because of the increasing number of large vehicles in the passing lane, violent on driving and traffic accidents in 2000. The needs of improvement on operating the lane designation has been increasing more in recent due to the low ratio of compliance with the system and difficulties to keep the right lane due to need of turning and demand of widening of designates lane for two-wheeled vehicles and truck. In this study, we presented the improvement plan through the question survey, simulation analysis, safety evaluation. It found a problem that the low-speed vehicle is to use the upper level roadway, difficulties of supervision, the imbalance in the lane use, imbalance traffic and does not match the international standards. This study suggested five different alternatives through the survey. micro simulation has used in order to examine each alternative by management effectiveness and feasibility. It analyzed the traffic speed, efficiency, traffic balance of alternatives. Also, safety evaluation conducted in terms of the range of field-of-view to ensure the easiness of field of view by various configurational difference between the vehicles. By the analysis results of such indicators, This study presents proposals for improvement in operating designated lane that low-speed-big-sized vehicles keep to the right lane, and high-speed-small sized vehicles keep to the left lane.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.35-35
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• 2017

How do plants take up water from soils especially when water is scarce in soils? Plants have a strategy to respond to water deficit to manage water necessary for their survival and growth. Plants regulate water transport inside them. Water flows inside the plant via (i) apoplastic pathway including xylem vessel and cell wall and (ii) cell-to-cell pathway including water channels sitting in cell membrane (aquaporins). Water transport across the root and leaf is explained by a composite transport model including those pathways. Modification of the components in those pathways to change their hydraulic conductivity can regulate water uptake and management. Apoplastic barrier is modified by producing Casparian band and suberin lamellae. These structures contain suberin known to be hydrophobic. Barley roots with more suberin content from the apoplast showed lower root hydraulic conductivity. Root hydraulic conductivity was measured by a root pressure probe. Plant root builds apoplastic barrier to prevent water loss into dry soil. Water transport in plant is also regulated in the cell-to-cell pathway via aquaporin, which has received a great attention after its discovery in early 1990s. Aquaporins in plants are known to open or close to regulate water transport in response to biotic and/or abiotic stresses including water deficit. Aquaporins in a corn leaf were opened by illumination in the beginning, however, closed in response to the following leaf water potential decrease. The evidence was provided by cell hydraulic conductivity measurement using a cell pressure probe. Changing the hydraulic conductivity of plant organ such as root and leaf has an impact not only on the speed of water transport across the plant but also on the water potential inside the plant, which means plant water uptake pattern from soil could be differentiated. This was demonstrated by a computer simulation with 3-D root structure having root hydraulic conductivity information and soil. The model study indicated that the root hydraulic conductivity plays an important role to determine the water uptake from soil with suboptimal water, although soil hydraulic conductivity also interplayed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.6
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• pp.559-570
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• 2013

High speed railway can transport large quantity of people and commodities in a short time and has become one of the most desirable and environmentally friendly transportation. However, it is hard to have a complicated route for high speed railways, construction of tunnels is essential to pass through a mountain area. When a high speed train enters a tunnel, pressure wave is created in a tunnel and the wave causes micro pressure wave and discomfort to passengers. In order to alleviate pressure wave in a tunnel, constructing a vertical shaft is one of the most efficient ways. This study represents a numerical analysis module, which takes into account the effect of a vertical shaft in a tunnel. The module can be used in a numerical program (TTMA) specialized for aerodynamics in a tunnel, and it was validated by comparing numerical results with various measurements in Emmequerung tunnel and results from numerical analysis using Fluent.

• Smart Media Journal
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• v.3 no.3
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• pp.46-50
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• 2014

Nowadays, mobile devices such as smartphones and tablet PC's are making big changes in our life. The most widely used mobile operating systems are Google's Android, Apple's iOS and Microsoft's Windows Mobile. Among them, Android has been researched in various electronic fields such as smartphones and tablet PC's as well as automobiles, Media oriented systems transport(MOST) is a standard for high-speed multimedia communications in automotive industries. In this paper, we present the design results of in-vehicle infotainment software using MOST network based on Android.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.3 s.8
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• pp.1-8
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• 2005

IEEE WAVE(Wireless Access in Vehicular Environment) is being developed to operate in 5 GHz DSRC band to provide cars moving at high-speed with vehicle-to-vehicle and vehicle-to-roadside communication. IEEE P 1609.3 of the WAVE protocol stack defines how multiple channels are used based on the exchange of provider-service-tables (PST) and user-service-tables (UST) for rapid link establishment and data transmission. This paper presents the design and implementation of an IEEE WAVE multi-channel transmission emulator that we have developed to study the operation of protocol and applications. Applications for a public-safety and a download service have been implemented and are shown to operate effectively on top of the emulator.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.411-427
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• 1996

A Lagrangian dispersion model has been developed to study the transport of atmospheric pollutants over the southern Korean peninsula on sunny summer days. A mesoscale atmospheric model has been employed to provide the wind fields and information for turbulent diffusion for the calculation of trajectories using a conditioned particle technique. The model has been applied to the simulation of the transport of atmospheric pollutants emitted from five sources in the coastal locations under various synoptic scale winds. Under calm synoptic scale condition, the particles emitted during daytime are mixed vertically and transported toward inland by sea-breeze, according to the model simulation. The particles are then transported upward at she sea-breeze front or by the upward motion over the mountain, and some particles show tendency of returning toward the coast by the return flow of the sea-breeze circulation. The particles are found to remain over the peninsula throughout the integration period under calm synoptic scale condition. When there is westerly synoptic scale winds the particles emitted in the west coast can reach the east coast within a day of faster depending on the speed. With a synoptic scale southerly wind of 5 m/s, most of the particles from the fine sources are advected toward inland during daytime. During nighttime, significant portion of particles released in the west coast remains over the land, while most particles released in the east coast move toward the sea to the east of the middle peninsula.

• Journal of Fisheries and Marine Sciences Education
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• v.13 no.2
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• pp.168-177
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• 2001

The flow pattern and water mass structure in the Chungmu channel were investigated using the field observations during June and July, 2001. The currents in the channel may be regarded as a hydraulic current decided by difference of tide levels between two sides in the channel. The strongest current in the channel occurs around in high water and low water. The coefficient C to be determined the characteristics of velocity in the channel was obtained from an equation, $u=C{\sqrt{2gh}}$ and ranges from 0.37 to 0.65 in the Chungmu Channel at the spring tide and from 0.23 to 0.37 at the neap tide. Eastward tidal transport is usually larger than that of westward transport in Chungmu the Channel. Sea water exchange rates are 39.2% in spring tide and 20.5% in neap tide respectively. The water mass structure in the channel is changed by the speed of the tidal current. The water mass is well mixed at the high water when the current is strong and is stratified at slack water when the current is weak.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.152-153
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• 2004

The growth rate of atmospheric $CO_2$ undergoes significant interannual variability, largely due to temporal variability of partitioning of $CO_2$ between terrestrial biosphere and ocean. In the present paper, as a follow-up to the work by Lee et al. [1], we estimated the year-to-year variability in net global air-sea $CO_2$ fluxes between 1982 and 2003 from observed changes in wind speed and estimated changes in ${\Delta}pCO_2$ Changes in $pCO_{25W}$ were inferred from global records of sea surface temperature (SST) anomalies and seasonally varying SST dependence of $pCO_{25W}$. The modeled interannual variability of $\pm0.2\;Pg\;C\;yr^{-1}\;(1{\sigma})$ from the present work is significantly smaller than the values deduced from atmospheric observations of $^{1.3}CO_2/CO_2$ in conjunction with different atmospheric transport models, but it is closer to the recent estimates inferred from a 3-D ocean biogeochemical model and atmospheric transport models constrained with extensive observations of atmospheric $CO_2$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.295-298
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• 2010

To find out moving and dissipation patterns of laid floating object estuary this paper has focused on forming, changing and variation of the wind forced river plume. In steady state(without external force), river can be form a bulge and downcoast alongshore current on gently sloped continental shelf. Under the downwelling wind and downcoast meanflow those river plume's patterns are similar with the steady state case except enhancement of downcoast transportation. Under the upwelling wind condition bulge linearly move to the northwest with 45 angle due to Ekman transport. It's moving speed are linear with the strength of the wind stress but moving paths are independent of that. So, in this case, floating object will be dissipate to outside as move to the upcoast.