• Journal of Digital Convergence
• /
• v.14 no.2
• /
• pp.217-225
• /
• 2016

In this study, a dementia patient care monitoring system is suggested that uses a wearable type bluetooth beacon to prevent them from going missing. This system shows whether the patients stay within the manageable area and sends a warning message to their monitoring managers' or guardians' smart devices when they leave it. The feature of the system is that it provides the service based on indoor location that makes the beacon worn by dementia patients continuously transmit their location information to the managing server through the smart terminal installed indoors or in hospitals and that enables the monitoring managers or the guardians to receive messages sent from the server that tell the patients' whereabouts through their smart devices. The system suggested in this paper is believed to be a system that effectively contributes to the prevention of the dementia patients' going astray from the hospitals and facilities where they are taking care.

• The Journal of Information Technology
• /
• v.3 no.2
• /
• pp.87-95
• /
• 2000

This paper studies on method about construction and design of two-way message system to overcome limit of one-way pager system. Method of two-way system construction is studied on using the present one-way pager system and configure system. Forward-link of proposed method is using the present one-way pager system. And Reverse-link of proposed method is used TRS and Beacon on pager. CTI(Computer Telephony Integration) is used to Call processing

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2009.06a
• /
• pp.375-378
• /
• 2009

AIS ship position transmitted from ships has been used position data generated by GPS, whose range of error is approximately 30nm. However, precision enhancement of the ship's position could be possible using DGPS correction information. More precise and accurate AIS ship position could be obtained broadcasting DGNSS Message(AIS Message 17) from ships without high-priced DGPS Beacon Receivers.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.4
• /
• pp.9-16
• /
• 2015

Quick and safe message transmission is an important research topic of vehicular ad hoc networks (VANET). Most studies assume that the periodic broadcast of beacon-frames between vehicles increases the safety of the driver. In this paper, we propose a medium access control (MAC) protocol and location-based clustering for the VANET to support reliable data transfer. In our proposal, the cluster heade (CH) manage the access and allocate the resources of the node. Our proposal uses simulation to confirm the reduction of the transmission delay and the collision rate of the signal.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.21-26
• /
• 2006

This paper focuses on modeling and predicting differential GPS corrections transmitted by marine radio-beacon systems using artificial neural networks. Various neural network structures with various training algorithms were examined, including Linear, Radial Biases, and Feedforward. Matlab Neural Network toolbox is used for this purpose. Data sets used in building the model are the transmitted pseudorange corrections and broadcast navigation message. Model design is passed through several stages, namely data collection, preprocessing, model building, and finally model validation. It is found that feedforward neural network with automated regularization is the most suitable for our data. In training the neural network, different approaches are used to take advantage of the pseudorange corrections history while taking into account the required time for prediction and storage limitations. Three data structures are considered in training the neural network, namely all round, compound, and average. Of the various data structures examined, it is found that the average data structure is the most suitable. It is shown that the developed model is capable of predicting the differential correction with an accuracy level comparable to that of beacon-transmitted real-time DGPS correction.

• Journal of KIISE:Information Networking
• /
• v.32 no.5
• /
• pp.633-640
• /
• 2005

This paper proposes and analyzes a message scheduling scheme and corresponding bandwidth allocation method for the hard real-time communication on dual standard 802.11 Wireless LANs. By making the superframeof one network precede that of the other by half, the dual network architecture can minimize the effect of deferred beacon and reduce the worst case waiting timeby half. The effect of deferred beacon is formalized and directly considered to decide the polling schedule of PCF phase. Simulation results executed via ns-2 show that the proposed scheme can improve the schedulability by 3$36\%$ for real-time messages and give $9\%$ more bandwidth to non-real-time messages for the given stream sets, compared with the network whose bandwidth is just doubled with the same MAC.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.48 no.4
• /
• pp.40-46
• /
• 2011

Wireless Sensor Networks(WSNs) have shown a lot of good outcomes in providing a various functions depending on industrial expectations by deploying ad-hoc networking with helps of light loaded and battery powered sensor nodes. In particular, it is strongly requested to develop an algorithm of cross-layer control between 2-layer and 3-layer to deriver the sensing data from the end node to the sink node on time. In this paper, based on the above observation we have proposed an IEEE802.15.4 based self priority routing scheme under UC Berkely TinyOS platform. The proposed beacon based priority routing (BPR) algorithm scheme utilizes beacon periods in sending message with embedding the high priority data and thus provides high quality of service(QoS) in the given criteria. The performance measures are the packet Throughput, delivery, latency, total energy consumption. Simulation results under TinyOS Simulator(TOSSIM) have shown the proposed scheme outcome the conventional Ad hoc On-Demand Distance Vector(AODV) Routing.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.12
• /
• pp.1195-1207
• /
• 2012

Fast and reliable message broadcasting is critical for safety critical applications of VANET due to the urgency and/or significance of the messages for passengers and drivers. For reliable message delivery, a mechanism for checking the reception of message at the neighboring vehicles and retransmitting it if necessary is required. Especially, in urban environments, where the traffic density tends to be high, mechanisms that minimize control message overhead such as beacon are appropriate in order to minimize the message collisions. Furthermore, broadcast delivery is especially difficult at the intersection due to the road side obstacles such buildings, and hence, a mechanism that enables effective and efficient delivery across intersections is required. In this paper, we propose a beaconless reliable and efficient broadcast approach which specifically taking into account the urban streets. The proposed approach checks the message reception of neighboring vehicles implicitly by taking into account the broadcast of message by next vehicle as the acknowledgement. When retransmissions is necessary around the intersections, vehicles located within the intersection area, where the chance of successful signal propagation toward every branch of the intersection is higher due to less signal attenuation caused by road side obstacles, are to do the retransmissions. Simulation results show that the proposed approach can provide better reliability while consume less resources than the existing approaches.

• Journal of Internet Computing and Services
• /
• v.15 no.3
• /
• pp.63-69
• /
• 2014

For the safety messages in IEEE 802.11p vehicles network environment(WAVE), strict periodic beacon broadcasting requires status advertisement to assist the driver for safety. WAVE standards apply multiple radios and multiple channels to provide open public road safety services and improve the comfort and efficiency of driving. Although WAVE standards have been proposed multi-channel multi-radio, the standards neither consider the WAVE multi-radio environment nor its effect on the beacon broadcasting. Most of beacon broadcasting is designed to be delivered on only one physical device and one control channel by the WAVE standard. also conflict-free channel assignment of the fewest channels to a given set of radio nodes without causing collision is NP-hard, even with the knowledge of the network topology and all nodes have the same transmission radio. Based on the latest standard IEEE 802.11p and IEEE 1609.4, this paper proposes an interference aware-based channel assignment algorithm with Nash bargaining solution that minimizes interference and increases throughput with wireless mesh network, which is deigned for multi-radio multi-cahnnel structure of WAVE. The proposed algorithm is validated against numerical simulation results and results show that our proposed algorithm is improvements on 8 channels with 3 radios compared to Tabu and random channel allocation algorithm.

• Journal of Digital Convergence
• /
• v.14 no.11
• /
• pp.241-247
• /
• 2016

As a domestic traffic control signal system, either the system with which a traffic signal turns into green at regular intervals or the system with which an amber or a red signal flickers on local roads without heavy traffic at midnight has been utilized. However, when the former system is used for roads with light traffic at midnight, delays and congestion can be incurred. Besides, in case of the latter signal system, the risk of vehicle crash is high. This study proposes a response type of flickering green signal system that rearranges signal system after analyzing beacon messages including sensor data. The proposed system, on a trunk road or a branch road at midnight, makes the signal keep flickering in green; When a vehicle enters the range of RSE, the transfer coverage, it transmits beacon messages regularly and Agent System analyzes the messages and alters the signal. It is a system by which vehicles move following the altered signal system, which will not only ensure smooth flow but also prevent vehicles from crashing on a road with light traffic. As a result of a simulation, traffic throughput and the average waiting time displayed 10 to 30 percent better improvement than existing signal systems, in terms of performance.