• Journal of Information Processing Systems
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• v.11 no.2
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• pp.295-309
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• 2015

Beacon scheduling is considered to be one of the most significant challenges for energy-efficient Low-Rate Wireless Personal Area Network (LR-WPAN) multi-hop networks. The emerging new standard, IEEE802.15.4e, contains a distributed beacon scheduling functionality that utilizes a specific bitmap and multi-superframe structure. However, this new standard does not provide a critical recipe for superframe duration (SD) allocation in beacon scheduling. Therefore, in this paper, we first introduce three different SD allocation approaches, LSB first, MSB first, and random. Via experiments we show that IEEE802.15.4e DSME beacon scheduling performs differently for different SD allocation schemes. Based on our experimental results we propose an adaptive SD allocation (ASDA) algorithm. It utilizes a single indicator, a distributed neighboring slot incrementer (DNSI). The experimental results demonstrate that the ASDA has a superior performance over other methods from the viewpoint of resource efficiency.

• Journal of IKEEE
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• v.22 no.2
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• pp.250-257
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• 2018

In this paper, a smart bus system that automates public bus traffic payment by applying beacon and computer vision and provides bus route information, real-time location information, getting off alarm is proposed. By using the beacon to recognize busses near the stop and to board the bus to be boarded, this system automatically processes the payment when boarding by using the distance from the beacon and the information provided by the beacon and the face comparison. After the payment processing, the system provides the route information of the boarded bus and the real-time bus location information to the user, and when the user sets an alarm using these informations, the alarm is activated when the bus leaves the bus stop.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.293-299
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• 2010

The multiple block localization method in a wide area for multiple robots using iGS is proposed in this paper. The iGS is developed for the indoor global localization using ultrasonic and RF sensors. To measure the distance between a mobile robot and a beacon, the tag on the mobile robot wakes up one beacon to send out the ultrasonic signal and measures the traveling time from the beacon to the mobile robot. As the number of robots is increased, the sampling time of localization also becomes longer. Note that only one robot can localize its own position calling beacons one by one during each of the sampling interval. This is a severe constraint for the localization of multiple robots in a wide area. This paper proposes an efficient localization algorithm for the multiple robots in a wide area which can be divided into multiple blocks. For a given block, a master beacon is designated to synchronize robots. By the access of the synchronization signal, each beacon in the selected group sends out an ultrasonic signal. When the robots in the block receive the ultrasonic signal, they can calculate their own locations based on the distances to the beacons, which are obtained by the multiplication of flight time and velocity of the ultrasonic signal. The efficiency of the algorithm is verified through the real experiments.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.27-34
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• 2014

Todays, the rapid technical progress of smart device has been used for various social (wall-fare) services in our lives. Especially, most of these services are based on the Local-based Services (LBS) and this technology is getting popular more and more compared with before. Basically, LBS is able to support various types of geographical services such as vehicles' navigation services, Augmented reality services as using extensional local information such as GPS. However, LBS has serious mathematical vulnerability on the services frequently because of its miscalculated GPS data under interior and ambiguous geographical environment such like shadowed area. So, to overcome this limitation, iBeacon, which would be able to mitigate LBS miscalculation process, has been proposed recently among network experts. Compared with other wireless technologies, iBeacon is able to determine the accurate geographical data of certain local positions easily because it is not only designed based on low-powered data transmitting technology, but also, it can be much easy to be deployed. As users' dependency of smart devices are getting higher and higher and the use of smart device is also getting complex more and more, the users prefer to use various types of smart devices at one time. Therefore, in this paper, we propose the loss prevention system that is able to interwork smart devices networks as using iBeacon technology for users' better conveniences.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1373-1382
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• 2011

Zigbee is communication technology most ideal because Zigbee support low power communication and wide expansion in wireless home network. However, Zigbee is not popular, because of Zigbee always has Hidden Node Problem and Transit Delay Problem. We propose new Beacon Frame structure to solve the two problem in Zigbee. New Beacon Frame structure reduces a Super Frame Duration and add a same space of a Control Frame Duration. We expect to solved method of Hidden Node Problem that exchange terminal information to using RTS/CTS. Also, We expect to solved method of Transit Delay Problem that put Beacon between Control Frame Duration and Super Frame Duration for synchronization. We confirm new Beacon Frame to solved two problem in OPNET simulation at Zigbee QoS Parameters. We measure Delay(sec) for solution degree of Transit Delay Problem, and measure Throughput(bits/sec) and Load (bits/sec) for solution degree of Hidden Node Problem.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.734-741
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• 2009

A new localization algorithm is proposed for a fast moving mobile robot, which utilizes only one beacon and the global features of the differential-driving mobile robot. It takes a relatively long time to localize a mobile robot with active beacon sensors since the distance to the beacon is measured by the traveling time of the ultrasonic signal. When the mobile robot is moving slowly the measurement time does not yield a high error. At a higher mobile robot speed, however, the localization error becomes too large to locate the mobile robot. Therefore, in high-speed mobile robot operations, instead of using two or more active beacons for localization, only one active beacon and the global features of the mobile robot are used to localize the mobile robot in this research. The two global features are the radius and center of the rotational motion for the differential-driving mobile robot which generally describe motion of the mobile robot and are used for the trace prediction of the mobile robot. In high speed operations the localizer finds an intersection point of this predicted trace and a circle which is centered at the beacon and has the radius of the distance between the mobile robot and the beacon. This new approach resolves the large localization error caused by the high speed of the mobile robot. The performance of the new localization algorithm has been verified through the experiments with a high-speed mobile robot.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.267-273
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• 2020

Beacon is a wireless communication device that can automatically recognize the smart device in the short distance and transmit the necessary data, Beacon is a representative Internet of Things (IoT) facility in the era of the 4th Industrial Revolution, which is utilized in various fields such as short-distance information delivery, mobile location service, shopping, and marketing, and is constantly evolving. In this paper, it is based on tourist site-based recommendation information service. A system is proposed that recommends customized information according to the user's interest, preference, etc. by incorporating beacon technology. In other words, it acts as an information agent that informs tourists of desired information. In order to meet the needs of tourists, it is necessary to build an intelligent tourism recommendation system. The personalized Korean food and tourism recommendation management system using the beacon technology proposed in this paper is expected to provide high-quality services not only to foreigners visiting Korea but also to Korean tourists.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4A
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• pp.365-372
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• 2007

In IEEE 802.11b wireless network, stations synchronize themselves to the beacons periodically sent by the access point(AP) when they are running in low power mode. In case of missing beacon due to noise or traffic from neighboring wireless network stations must be awake until they get the next beacon, which causes energy consumption in stations. In this paper, we propose a scheme searching next beacon consuming little energy. The problems of missing beacon in low power mode of IEEE 802.11b wireless interface are described and a new method to reduce energy consumption is proposed. The proposed method is simulated with the network simulator, ns2, and compared with the low power mode of the IEEE 802.11b. The result measured in terms of station's wakeup time shows some enhancement in energy consumption when some errors occur in receiving frames.

• Journal of KIISE
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• v.42 no.2
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• pp.272-279
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• 2015

Concurrent with the more widespread usage of smart devices, mobile users' desires are becoming much more complex. Most IT experts insist that smart devices should have additional functions to satisfy these requirements. In particular, research has concentrated on LBS (Locationbased Service), because it is considered one of the most common mobile service types. Generally, Wi-Fi has a critical limitation for use for LBS services, because it requires new network connection points whenever its location (Network Zone) changes. Unfortunately, GPS also has a systematic problem in providing LBS service in the indoor environment, because of its inaccuracy in processing data. So, to redress these limitations, iBeacon technology has been designed, and is currently used for LBS service instead of Wi-Fi or GPS. By using iBeacon, which is based on Bluetooth 4.0 LE technology, we propose a M-SAS (Mobile-Subway-Alarm-Service System) that could accurately and timely provide its users with various mLBS (micro LBS) services, such as current user location, and subway arrival time.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.231-238
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• 2017

A Class B device in LoRaWAN periodically receives a Beacon message from a gateway for synchronization, and it also periodically activates a ping slot to receive data from the server. In this paper, we save energy consumption by controlling the beacon-less operation which is immediately started on the packet loss. In addition, we propose a method that the server inactivates the ping slots of a device according to the amount of messages, which have to be received from the server, to save energy consumption resulting from activated but unused empty slots. The experiment with the 20% of packet loss rate showed that the reduced beacon-less operation and the inactivation of the ping slot decrease the energy consumption by 96.7% and 60% as compared to the existing method.