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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of The Korea Institute of Intelligent Transport Systems
Journal Basic Information
Journal DOI :
The Korea Institute of Inteligent Transport Systems
Editor in Chief :
Volume & Issues
Volume 7, Issue 6 - Dec 2008
Volume 7, Issue 5 - Oct 2008
Volume 7, Issue 4 - Aug 2008
Volume 7, Issue 3 - Jun 2008
Volume 7, Issue 2 - Apr 2008
Volume 7, Issue 1 - Feb 2008
Selecting the target year
Bus Reliability Management Policy and Evaluation of Seoul Metropolitan Based on APTS Data
Lee, Ho-Sang ; Lim, Jung-Sil ; Jung, Young-Jae ; Kim, Young-Chan ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 1~12
Recently, the roll of bus transit is critical more than before because of the dramatical increase in congestions and oil prices, but bus companies seriously encounter into vicious circle situation such as decrease in passenger demand, income reduction, and revenue deterioration. To tackle this, major metropolitan cities, Seoul, Busan, DaeGu, etc. have introduced a semi-public system to reinforce public function of bus. However, it was resulted in side effects that the main board of bus company did not control theirselves voluntarily, and the management and control of public sectors on bus become very important elements. In this research, the types, limitations, and development of operation-management items, and a methodology for analysis, and changes in those trends are addressed under semi-public system using APTS data. Conclusively, this study could be one of the useful application results and alternatives for the operation-management policy of bus transit-related agencies.
A Study on the Location Awareness System Using TOA(Time of Arrival) of CSS(Chirp Spread Spectrum) Algorithm
Kim, Jung-Soo ; Yang, Jin-Uk ; Yang, Sung-Hyun ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 13~25
In this paper, we propose the Location Awareness System adjusting Ranging Technology for CSS(Chirp Spread Spectrum) which is adopted on 2.45GHz standard in IEEE 802.15.4a and TOA(Time-of-Arrival) algorithm. The conventional methods have adopted RSSI, ultrasonic waves and infrared rays in Zigbee. RSSI measures strength indication of received signal and recognizes the position of nodes in RF boundary. However, this technology has the following problems; lots of error by the change of the channel environment and much power consumption. In this paper, adopting chirp pulse on 2.45GHz standard in IEEE 802.15.4a and SDS-TWR(Symmetrical Double Side-Two Way Ranging) method using the characteristic of Spread Spectrum, a new Location Awareness System is suggested. The distance and the coordinate are measured within
by TOA(Time of Arrival) algorithm and proposed algorithm and the data in error rate is decreased less than 1%. Through these results, the algorithm suggested in this paper is verified for its performance in a computer simulation.
Development of Pedestrian Signal Timing Models Considering the Characteristics of Land Use and Pedestrians
Hwang, Duk-Soo ; Oh, Young-Tae ; Lee, Sang-Soo ; Lee, Choul-Ki ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 26~36
Currently, the pedestrian signal timing model has no consideration on the characteristics of different land use patterns and pedestrian behaviors during pedestrian signal timing calculation. This study intended to propose pedestrian signal timing models that could reflect the inherent characteristics of pedestrian and land use patterns. For this study, three major variables affecting the length of signal timing were identified: walking speed, perception-reaction time, and density-delay time. Then, the representative values of each variable were estimated through the field studies. By combining this information, several pedestrian signal timing models were developed. The data in this paper can be used for future references, and the walking environments for pedestrians could be improved by applying the models suggested in this paper.
A Study on Vocabulary-Independent Continuous Speech Recognition System for Intelligent Home Network System
Lee, Ho-Woong ; Jeong, Hee-Suk ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 37~42
In this paper, the vocabulary-independent continuous speech recognition system for speech control of intelligent home-network is presented. This study suggests a conversational scenario of continuous natural vocabulary based upon keywords for recognition on natural speech command, and a way of optimizing the recognition system by constructing a recognition system and database based upon keywords.
Design of Directional Coupler for TX/RX Isolation in UHF Band RFID Application
Na, Won ; Kim, Wan-Kyu ; Yu, Jong-Won ; Lee, Moon-Que ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 43~49
In this paper, new directional couplers for T/R switch of UHF RFID applications are proposed to overcome TX-to-RX leakage problem. The proposed method can remove TX-to-RX leakage caused by both imperfect isolation characteristic of the conventional directional coupler and the mismatch of antenna impedance. Two directional couplers are implemented using distributed elements and lumped elements respectively for the verification. The varactor tuneable circuits for compensation of the antenna mismatch is also proposed. The measurement result shows excellent TX-to-RX leakage suppression, more than 45dB in 910MHz.
Frequency and Input Impedance Selective Antenna Using Lumped Element for Multi-band Handhold Terminals
Jung, Byung-Woon ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 50~55
In this paper, multi-band internal antenna which can adjust both resonant frequency and input impedance of antenna as using lumped inductor between shoring plate and ground plane is proposed. The structure of proposed antenna consists of PIFA (Planar Inverted F Antenna) structure and half-wavelength loaded line structure and has two shorting plates and one feeding plate. One shorting plate is shared. The operating frequency bands of designed antenna are GSM, GPS in the PIFA structure and DCS, US-PCS, W-CDMA in half-wave loaded line structure as varying the inductor value in 2.2nH, 3.3nH, and 4.7nH. As varying the inductor value in the shared shorting plate, input impedance of antenna is varied. To minimize the gain variation of antenna as adding lumped element, the inductor value is restricted at maximum of 6.8nH. The maximum gain of proposed antenna is measured as -1.60dBi in the GSM band, -1.16dBi in the GPS band, and 1.41dBi in the DCS/US-PCS/W-CDMA band.
Polarization Diversity Antenna for Receiving Traffic Information Contents in WiBro System
Jung, Byung-Woon ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 56~61
Diversity antenna system against multi-fading environment is strongly required for WiBro service of vehicle. In general, high isolation performance between antennas leads to good diversity gain. In this paper, a polarization diversity antenna is presented, which has orthogonal polarizations and good isolation characteristic. In addition, by simulation and measurement, it is certified that HWLLA (Half Wave Length Loaded Antenna) improves polarization purity on common ground. In isolation between two antennas, HWLLA can provide better isolation over 12dB than conventional PIFA (Planar Inverted F Antenna).
The Improvement of Linearity in Power Amplifier Using Anti Phase Intermodulation Distortion Linearization Technique
Jang, Jeong-Seok ; Do, Ji-Hoon ; Kang, Dong-Jin ; Kim, Dae-Woong ; Kim, Dae-Huo ; Hong, Ui-Seok ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 62~69
This paper proposes linearization technique that the linearity is improved by controlling IMD between the drive stage and the output stage. From the experimental results of W-CDMA 4FA input signal, this amplifier has ACLR of -48dBc@5MHz offset at 50W average power. Proposed linearization technique provides predistortion effect for using drive amplifier without additional circuit, which is the significant in this paper that it makes up for the weak point of analog predistortion method and feedforward method.
Dynamic CSMA Protocol Based on the Network Status
Lee, Wang-Jong ; Rhee, Seung-Hyong ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 70~80
CSMA(Carrier Sense Multiple Access) is a media access control protocol when nodes use a shared channel. To reduce the probability of collision and increase the performance, the station lust checks the state of the channel. In this paper, we study the performance improvement method based on p-persistent strategy. The p-persistent method reduces the chance of collision and improves the efficiency. However, a probability p and the number of station affect the performance. This paper proposes a dynamic CSMA multiple access based on the network status. If the possibility of collision is low, the station increases the probability p to improve the performance. In the opposite case, the station decreases the probability p. Our simulation results show that the proposed scheme outperforms any methods of CSMA multiple access according to the current persistent strategy.
An Energy-efficient MAC Protocol in Cognitive Radio Environment
Kim, Byung-Boo ; Rhee, Seung-Hyong ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 81~91
In mobile wireless communications, there is a new approach that uses the lacking spectrum efficiently. A cognitive radio is a device that can changes its transmitter parameters based on interaction with the environment in which it operates. At present, the wireless communication standard for wireless device contains power-saving modes or energy efficient mechanisms which cuts off the power of transmitter and receiver for power-saving. However, in cognitive radio environment, every device has the Quiet Period for searching channel and existing energy-saving method is not appropriate to be adjust to cognitive radio environment. In this paper, we propose an energy-efficient MAC protocol of mobile device in cognitive radio environment and prove the improvement of proposed method.
A Study on Economic Analysis of Improvement of High Accident Locations in Highway(Focused on Safety Facilities)
Park, Je-Jin ; Joo, Jae-Woong ; Lee, Jong-Chul ; Ha, Tae-Jun ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 92~99
The rapid economic growth in Korea raised the increase of transportation demands about the passengers and the goods, and caused the concentration on cities. By the rise of a nation's income level, a automobile is necessary in our modern life. However, the traffic delays and traffic accidents that are raised by automobiles decrease the evaluation about a nation's economy and then the government practices the traffic safety improvement project. In this study, by performing the improvement project, we expect to achieve the following objectives. First, this study analyses the degree of effectiveness whether or not success in the improvement. Second, to supply the data on the effectiveness of the improvement and to inform the necessity of improvement. Third, to supply the information on the improvement project to the parties concerned. In this paper, through the study about identification of high accident locations, the effectiveness for the number of accidents and accident rates before-after the improvement is analyzed. Also, the B/C analysis about this locations is performed. This study shows that the number of accident and accident rates are decreased after the improvement, and there is economic validity about improvement of high accident locations.
Criteria of Installing Delineators Considering Human Factors
Park, Je-Jin ; Park, Tae-Hoon ; Ha, Tae-Jun ;
The Journal of The Korea Institute of Intelligent Transport Systems, volume 7, issue 2, 2008, Pages 100~109
Traffic accidents at night occur more than any other time because of improper road light facility and delineators. Therefore, cost-effective criteria of installing delineators are needed instead of expensive road light facility, especially, on rural road including light volume of traffic. This paper presents the criteria of installing 'Chevron Alignment Sign' considering driver's visual behavior characteristics and 'Raised Pavement Marker' considering critical encroachment angie of both straight section and curve one in order to reduce both the number of accidents on curve sections and the number of road encroachment accidents, respectively. The characteristics of visual behaviors can be expressed by visual angle involving curve radius and intersection angle. The estimated installing angles are
by radii, which is based on changes in sensitivity across visual field by exogenous attention. Also, the raised pavement marker is installed every 2m, 3m, and 4m considering critical encroachment angles by radii.