• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.15-25
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• 2007

This paper aims at testing the applicability of RFID (radio frequency identification) based link travel time estimation algorithm in urban street settings in Jeju island Korea. For this, we developed algorithm and compared link travel times derived from the RFID probe based algorithm with those from (already available) GPS based link travel time estimation algorithm and with the actual link travel times from survey. RFID readers are composed of master reader and slave reader and the participating passenger cars were supposed to be equipped with RFID tag inside the vehicle. The data were sent to traffic information center and we used those data in comparison. The algorithm produced link travel times in a successful manner and the accuracy of those link travel times was about 88%. For the same link segments, the accuracy of GPS based link travel times was 93%. The t-test showed that both RFID and GPS based link travel times were not different in accuracy from statistical point of view. The applicability of RFID was tested successfully and the algorithm proposed seemed to be used in similar urban settings. Some limits and future research agenda have also been presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.1 s.12
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• pp.13-26
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• 2007

A VDS data in the domestic has been used within limits to real time information such as congestion management, incident management, and route guidance service. On the other hand, a VDS data in the foreign countries had been used to various objectives such as transportation policy assessment, transportation construction evaluation, franc safety improvement, and etc. The scope and method of the study is the VDS data which was installed in the uninterrupted flow such as the freeway and the interrupted flow in a diversion route of the leeway. It has investigated and analyzed the VDS as our subject to study, study objective and study methodology for each study generally classified as 1) data collection 2) data processing 3) data store and 4) data quality section. This study has investigated and analyzed the various literatures in domestic and foreign countries regarding the VDS data. And It drew the development direction of the study which is about VDS data in domestic from now.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.42-52
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• 2012

In this paper, a waveguide antenna is designed and fabricated for side and rear radar sensor of vehicles in UWB (Ultra Wide Band) high band (center frequency : 9.5 GHz, -10 dB bandwidth : 600 MHz (6.4 %)). For the radar antenna, a probe fed rectangular waveguide antenna having simple structure and wide bandwidth is used. An important performance factor in this antenna is the isolation between transmitting (TX) and receiving (RX) waveguide antennas because this radar system uses TX and RX antennas separately. Thus the isolation between two antennas was simulated for E-plane and H-plane array. As a result, it was verified that the isolation of the H-plane array of the antennas is better than E-plane array, due to the TE10 mode. Therefore, H-plane arrayed waveguide antennas were mounted on a T-shaped radar module and performance of antennas was investigated. The -10 dB bandwidth of the TX and RX antenna mounted on T-shaped radar module was measured as 1000 MHz (10.52 %) and 1090 MHz (11.47 %) respectively and the isolation is less than -50 dB in the operation band. The peak gain is 7.65 dBi for the TX antenna and 7.26 dBi for the RX antenna and the beamwidth of H-plane of TX and RX antenna was measured as $64^{\circ}$ and $65^{\circ}$ respectively. Consequently, we verified that the proposed waveguide antenna is appropriate for a vehicle radar applications.

• The Journal of Society for e-Business Studies
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• v.18 no.1
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• pp.71-95
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• 2013

This study aims to validate the cost of building the infrastructure to commercialize online electric vehicles. For that purpose, we probe the cost to construct the necessary infrastructure for online electric vehicles regarding Seoul area public bus transit. OLEV and PEV are considered as alternative electric vehicle schemes, and each of them has their own cons and pros in terms of rechargeable battery cost and charger cost. An optimization model which minimizes the cost to install online electric bus feeding devices is proposed in order to compare the total costs of the two alternative schemes. We developed a Mixed Integer Programming model to locate the feeding devices of several different lengths at each bus stops. Furthermore, we implemented a computer simulator to obtain the parameters which will be used in the MIP model and a Web-based system which determines the optimal location of infrastructure for the whole city area from a result of the MIP model. The cost comparison result shows that the total cost of OLEV is cheaper than that of PEV considering the real data of Seoul area public transit, and, as a result, confirms the feasibility of the commercialization of OLEV.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.73.1-73.1
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• 2010

For the successful cold starting of a fuel cell engine, either internal of external heat supply must be made to overcome the formation of ice from water below the freezing point of water. In the present study, switchable vanadium oxide compounds as variable temperature-electrical resistance materials onto the surface of flat metallic bipolar plates have been prepared by a dip-coating technique via an aqueous sol-gel method. Subsequently, the chemical composition and micro-structure of the polycrystalline solid thin films were analyzed by X-ray diffraction, X-ray fluorescence spectroscopy, and field emission scanning electron microscopy. In addition, it was carefully measured electrical resistance hysteresis loop over a temperature range from $-20^{\circ}C$ to $80^{\circ}C$ using the four-point probe method. The experimental results revealed that the thin films was mainly composed of Karelianite $V_2O_3$ which acts as negative temperature coefficient materials. Also, it was found that thermal dissipation rate of the vanadium oxide thin films partially satisfy about 50% saving of the substantial amount of energy required for ice melting at $-20^{\circ}C$. Moreover, electrical resistances of the vanadium-based materials converge on an extremely small value similar to that of pure flat metallic bipolar plates at higher temperature, i.e. $T{\geq}40^{\circ}C$. As a consequence, experimental studies proved that it is possible to apply the variable temperature-electrical resistance material based on vanadium oxides for the cold starting enhancement of a fuel cell vehicle and minimize parasitic power loss and eliminate any necessity for external equipment for heat supply in freezing conditions.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.169-175
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• 2004

This paper develops a dynamic travel time prediction model for ATIS in a national highway. While there have been many research on travel time prediction, none of them is for national highway in Korea. The study uses AVI data installed on the national highway No.1 with 10km interval for travel time prediction model, and probe vehicle data for evaluating the model. The study area has many access points, so there are many outlying observations in the raw AVI data. Therefore, this study uses the algorithm proposed by the author for removing the outliers, and then Kalman filtering algorithm is applied for the travel time prediction. The prediction model is performed for 5, 10, 15 and 30 minute-aggregating interval and the results are $0.061{\sim}0.066$ for 5, 10 and 15 interval and 0.078 for 30 minute one with a little low performance as MAREs.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.29-41
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• 2017

In this study, we used individual trip data to estimate a macroscopic fundamental diagram (MFD) that relates flow (or production) to density (or state) in Daegu metropolitan city. The individual trip data were generated by processing data that were collected from DSRC-based (dedicated short range communication) traffic data collection system. Using the processed individual trip data, we first examined whether the assumptions for MFD are valid, and then the relation between outflow and accumulation was estimated in our study site. As a result, we found that i) the assumptions are valid to construct MFD; and ii) the reproducible and well-defined MFDs exist in the network level.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.1-6
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• 2004

Tetracycline resistant bacterial strains were isolated from 10 batches of Kimchi among 50 batches collected in Taegu restrict. The MIC of tetracycline ranged between 25 and> 100 ㎖/l. Total genomic DNA preparation from all 10 tetracycline resistant lactic acid bacterial isolates were subjected to PCR amplification with class-specific primers for tet(M) and tet(O). In only one isolate, HJ9, tet(M) was detected. By Southern blotting and hybridization with a tet(M)-specific probe, the tet(M) gene of HJ9 isolate could be localized on a plasmid. The partial nucleotide sequence and deduced amino acid sequence of tet(M) of HJ9 showed 90-99% and 94-100% homology to those of Gram positive bacteria, respectively. With sequencing of 16S rRNA, HJ9 isolate from Kimchi was identified as Lactobacillus sakei. From these results, Kimchi can be considered potential vehicle for the spread of antibiotic-resistant lactic acid bacteria along the food chain to the consumer.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.156-161
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• 2015

In this paper, a dual-polarized multi-band multi-layer antenna for a vehicle, which operates in the GPS, bluetooth, and DSRC bands, was implemented. The antenna was designed as a multi-layer structure, and a FR4-epoxy substrate with =4.4 and =1.6mm was used. GPS and DSRC antennas have circular polarized characteristics, and a single probe feeding method was applied. Simulated results by Ansys HFSS v11 was compared with the measured ones. The size of the optimally designed antenna is $67mm{\times}67mm{\times}4.8mm$, -10dB bandwidth of the anatenna was measured to be 820MHz, 127MHz, and 862MHz in each band, and 3dB AR bandwidth of the antenna was simulated to be 19MHz and 110MHz in GPS and DSRC bands. The results confirmed that suggested system satisfies the system requirements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.53-63
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• 2008

In this paper, we propose the regional travel time measurement algorithm using the sequence pattern matching to the type of vehicles between the origin of the region and the end of the region, that could be able to overcome the limit of conventional method such as Probe Car Method or AVI Method by License Plate Recognition. This algorithm recognizes the vehicles as a sequence group with a definite length, and measures the regional travel time by searching the sequence of the origin which is the most highly similar to the sequence of the end. According to the assumption of similarity cost function, there are proposed three types of algorithm, and it will be able to estimate the average travel time that is the most adequate to the information providing period by eliminating the abnormal value caused by inflow and outflow of vehicles. In the result of computer simulation by the length of region, the number of passing cars, the length of sequence, and the average maximum error rate are measured within 3.46%, which means that this algorithm is verified for its superior performance.