• Journal of Navigation and Port Research
• /
• v.29 no.10 s.106
• /
• pp.827-832
• /
• 2005

In this paper, as a fundamental study of ship collision avoidance supporting system in close quarters situation, we propose ship collision avoidance support model for decreasing ship collision accidents those have occurred due to navigator's unsuitable maneuvering in close encounter. This model will effectively support maneuvering for collision avoidance through displaying the feasible area and the method of collision avoidance using own ship's turning characteristic about action of target ship's keeping course and velocity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.4
• /
• pp.398-414
• /
• 1992

For designing the radar integrated data network, we construct the network structure with a spatial hierarchy decomposition scheme. The RIDN can be decomposed into several subnet classes, those of which are composed of the several group classes of radar sits, In a group class, the communication nodes of a radar site are modeled by the software modules formulated with the statistical attributes of discrete events. And we get the analysis over the network through the separately constructed infra group level models which were coded with the C language. After constructing the local area network with these infra models through the proper data links. We got the analysis of the communication performance of inner models and the global network.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.29 no.1
• /
• pp.119-124
• /
• 2005

In this paper, as a fundamental study of ship collision avoidance supporting system in close quarters situation, we propose ship collision avoidance support model for decreasing ship collision accidents those have occurred due to navigator's unsuitable maneuvering in close encounter. This model will effectively support maneuvering for collision avoidance through displaying the feasible area and the method of collision avoidance using own ship's turning characteristic about target ship's keeping course and velocity maneuvering actions.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.4B
• /
• pp.245-256
• /
• 2003

2-D OCDMA is considered to be a viable technical solution for optical LANs, and a considerable amount of research effort has been devoted to various 2-D OCDMA techniques. In this paper, we propose two new interference model for 2-D OCDMA LANs employing unipolar random codes, and derive maximum-likelihood detectors based on these interference models. The BER performance of the maximum likelihood detectors and that of other existing detectors are compared through extensive computer simulation. In addition, the complexity of high-speed implementation of the detectors is assessed, and as a result, we found that the AND detector and the maximum-likelihood detectors for the pulse-binomial and the pulse-Poisson model offer the best trade-off between the BER performance and the facility of high-speed implementation.

• The KIPS Transactions:PartC
• /
• v.13C no.5 s.108
• /
• pp.567-574
• /
• 2006

VG-AnyLAN is a local area network standard developed by the IEEE 802.12 project. While preserving the frame format of IEEE 802.3, VG-AnyLAN adopts a new medium access control called Demand Priority where transmission requests of stations are arbitrated by a control hub in a round-robin manner. Unlike CSMA/CD which is the medium access control of IEEE 802.3, the Demand Priority, while providing the maximum bound on the packet delay, does not put the limit on the network segment size. In this paper, we analyze the delay and the channel utilization performances of the medium access control of IEEE 802.12 VG-AnyLAN. We develope an analytic model of the system under assumptions that each station generates traffic of the equal priority and that the packets are of fixed length. Using the analytic model, we obtain the recursive expression of the average channel utilization and the average access delay The numerical results obtained via analysis are compared to the simulation results of the system for a partial validation of our analysis.

• Geophysics and Geophysical Exploration
• /
• v.2 no.1
• /
• pp.43-53
• /
• 1999

Numerical modeling and inversion for electromagnetic exploration methods are essential to understand behaviour of electromagnetic fields in complex subsurface. In this study, a finite element method was adopted as a numerical scheme for the 2.5-dimensional forward problem. And a finite element equation considering linear conductivity variation was proposed, when 2.5-dimensional differential equation to couple eletric and magnetic field was implemented. Model parameters were investigated for near-field with large source effects and far-field with responses dominantly by homogeneous half-space. Numerical responses by this study were compared with analytic solutions in homogeneous half-space. Blocky inversion model was modified to be applied to the forward calculation in this study and it was also adopted in the inversion algorithm. Resolution for isolated bodies were investigated to confirm possibility and limitation of inversion for electromagnetic exploration data.

• Journal of Digital Contents Society
• /
• v.19 no.3
• /
• pp.569-577
• /
• 2018

Near-Field Communication(NFC) is a useful technology that is receiving worldwide attention. NFC mobile payment systems are being developed by many technology companies including financial institutions especially for the public transportation. In this research we find several factors for the intention to adopt NFC payment system. We surveyed 355 respondents who live in Ho Chi Minh city, Vietnam which became more interested by Korean as a post China country to test our research hypothesis. Using Technology Acceptance Model(TAM) we find that the factors of Social influence, Trust, Security, and Users' Convenience play the significant role to the factor of Intention to Use of NFC payment system.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.2
• /
• pp.1-6
• /
• 2010

Short-range wireless communication systems are expanding at rapid rate, finding application in offices and homes. Development of wireless local network is accompanied by steady increase in the demand for ever higher data rates. This in turn entails the necessity to develop communication systems which operate at higher frequencies. It can be expected that short-rage wireless communication networks will soon push towards the THz frequency range. We use a 3D ray-launching for analysis of propagation environments at the indoor fixtures. We extended the approach from the modeling of the reflectivity of optically thick, smooth building materials at THz frequencies to materials with a rough surface. The simulation result of propagation environment is similar to average received power of reference paper. The RMS delay spread was calculated to be 9.11 ns in a room size of $6m(L){\times}5m(W){\times}2.5m(H)$ for the concrete plaster.

• Journal of Industrial Convergence
• /
• v.16 no.3
• /
• pp.33-40
• /
• 2018

Near Field Communication has been emerged as a spectacular phenomenon. The aim of this study is to determine the factors influencing the adoption of NFC-enabled mobile payment. In order to analyze, this study proposes a research framework based on Technology Acceptance Model. 353 valid data were collected through the Internet who has used NFC technology. Results show that relative advantage, social influence, and technology availability have a significant effect on perceived usefulness ($0.190{\ast}{\ast}{\ast}$, $0.211{\ast}{\ast}{\ast}$, $0.227{\ast}{\ast}{\ast}$respectively). However, for perceived ease of use, only relative advantage and social influence were verified to have significant influence. Perceived ease of use significantly influence perceived usefulness ($0.348{\ast}{\ast}{\ast}$), and both of them significantly affect the NFC-payment adoption intention ($0.199{\ast}{\ast}$, $0.361{\ast}{\ast}{\ast}$). The results also verified the moderator variable of personal innovativeness ($0.20{\ast}{\ast}{\ast}$ and $0.297{\ast}{\ast}{\ast}$respectively).

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.9
• /
• pp.3037-3047
• /
• 2000

This paper describes a method of tracking a close leading vehicle by color image processing using the pairs of tail and brake lights. which emit red light and are housed on the rear of the vehicle in stop-and-go traffic condition. In the color image converted as an HSV color model. candidate regions of rear lights are identified using the color features of a pair of lights. Then. the pair of tailor brake lights are detected by means of the geometrical features and location features for the pattern of the tail and brake lights. The location of the leading vehicle can be estimated by the location of the detected lights and the vehicle can be tracked continuously. It is also possible to detect the braking status of the leading vehicle by measuring the change in HSV color components of the pair of lights detected. In the experiment. this method tracked a leading vehicle successfully from urban road images and was more useful at night than in the daylight. The KAV-Ill (Korea Autonomous Vehicle- Ill) equipped with a color vision system implementing this algorithm was able to follow a leading vehicle autonomously at speeds of up to 15km!h on a paved road at night. This method might be useful for developing an LSA (Low Speed Automation) system that can relieve driver's stress in the stop-and-go traffic conditions encountered on urban roads.