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A fast 3-D ray tracing method based on image theory is presented. The proposed method defines reflection tubes and organizes them in a tree structure to treat images efficiently in a complex 3-D environment. The method can account for all possible rays undergoing multiple reflections and transmissions, and its predictions agree well with the measurements.
Recently, industry demands systematic safety management to decrease accident rates. However, existing safety management in industry worksites depends on a small number of safety supervisors. In particular, in case of shipbuilding industry, thousands of workers are working concurrently in wide areas of worksites. Therefore, choosing and monitoring high risk zones by priority at current status in time...
For the safety and convenience of driving, vehicle should provide adaptive interaction strategy to driver's characteristics and status. For this purpose, we began developing the driver-adaptive vehicle interaction system (DAVIS). Our system is going to provide adequate interaction mechanism based on the characteristics of the driver in addition to the driver's status varying in real-time. As the first...
In this study, we introduce an efficient dual-band polar transmitter architecture to reduce the required bandwidth of phase-modulated signal for polar transmitter. We derive a time-domain expression of dual-band band-pass signal, and show comparison of receiving signal-to-noise performance between the conventional polar transmitter and the proposed scheme. Simulation results show two-stage digital...
Recently, demands for developing offshore plants are increasing. Accordingly, the amount of orders of offshore plants exceeds 50 percent of total shipbuilding contracts of shipyards in South Korea. Also, occurrence rates of incidents in building offshore plants are increasing. In this respect, it is required that a safety management system is built for each shipyard or offshore plant building project...
In recent years, demands about offshore plant developments are increasing. Since the cost of installation of offshore plants in the deep ocean is very high, operation and realtime monitoring of offshore plants is not only important to produce a high performance such as tremendous profits but maintenance of them is also crucial to prevent accidents. However, since offshore plants are custom built compared...
Detection of urgent events shortens the sensing period for correct information. This causes traffic congestion in the network, resulting in possible overflow of data queue of sensor nodes and loss of important information. A new congestion control method based on a generalization algorithm is proposed. The proposed method selects data forwarding nodes that distribute the congested traffic over other...
The Shipdex protocol is the international business rules developed to standardize the development and the exchange of technical and logistic data within the shipping community. Shipdex defines rules for authoring a data module in XML format which is the smallest independent information unit. In order to validate whether a data module has been generated in accordance with Shipdex protocol, it is necessary...
Since sensor nodes operate on the same timeline, for successful cooperation, time synchronization is an important requirement in a wireless sensor network. Message packets with time information are used for this time synchronization. However, since wireless sensor nodes have limited battery capacities, the excessive use of message packets shortens their lifetimes. In this paper, a reference interpolation...
In maritime communication, QoS problem caused by routing is very important. In this paper, we propose a method based on AOMDV protocol providing a route recovery mechanism when a link breaks in an active route to reduce lost packets. The results show that the proposed method can reduce packet loss ratio and delay time compared with the AOMDV.
In this paper, we present PGS, a parking guidance system based on wireless sensor network(WSN) which guides a driver to an available parking lot. The system consists of a WSN-based VDS(vehicle detection sub-system) and a management sub-system. The WSN based VDS gathers information on the availability of each parking lot and the management sub-system processes the information and refines them and guides...
In this paper, we present a wireless sensor infrastructure for traffic safety. Real time information and possible dangerous situations are detected by wireless sensors installed in the roadway. The information is used to provide warning messages to drivers. We designed and implemented a flexible TDMA-CMSA/CA hybrid medium access control (MAC) protocol for wireless sensors guaranteeing deterministic...
We designed RRMAC, a time division multiple access (TDMA) scheme guaranteeing hard real-time and reliable communication in a multi-hop convergecast network. We performed experiments to compare the performance of RRMAC and IEEE 802.15.4 and showed the advantages of RRMAC is WSN applications which require highly reliable real-time data transmission.
In this paper, we propose a medium access control (MAC) protocol for supporting telematics service in the road environment, which requires the guarantee of a delay bound on end-to-end transmission and high transmission reliability in a multi-hop network. In order to guarantee a delay bound on end-to-end transmission and high transmission reliability in a multi-hop network, the proposed MAC adopts...
The demand for the safety is increased in the telematics area. The main reason for the car accident is driver's delay in recognition and error in operation and judgment about danger. About 45 % car crash comes from delayed recognition and 28 % comes from error in operation and judgment. In order to solve the safety problem, we propose the wireless sensor system which can reduce the danger by warning...
The demand for the safety is increased in the telematics area. The main reason for the car accident is driver's delay in recognition about danger. About 45% car crash comes from delayed recognition. In order to solve the safety problem, we propose the wireless sensor system which can reduce the danger by warning invisible and unexpected risk in advance. In the consideration of environment which our...
It is becoming desirable for users to easily and instantaneously use software anywhere and anytime. However, current telematics service platform, i.e. downloading, installing and configuring software, is not feasible for it. In this paper, we propose a new software streaming system called TeleASP. The TeleASP creates virtual applications from legacy application without modification. The virtual application...
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