• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.306-311
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• 2017

In the future ubiquitous network, information will collect data from various sensors in the field. Since the sensor nodes are equipped with small, often irreplaceable, batteries with limited power capacity, it is essential that the network be energy-efficient in order to maximize its lifetime. In this paper, we propose an effective network routing method that can operate with low power as well as the transmission of data and information obtained from sensor networks, and identified the number of sensors with the best connectivity to help with the proper placement of the sensor. These purposes of this research are the development of the sensor middle-ware to integrate the maritime information and the proposal of the routing algorithm for gathering the maritime information of various sensors. In addition, for more secure ship navigation, we proposed a method to construct a sensor network using various electronic equipments that are difficult to access in a ship, and then construct a communication system using NMEA(the national marine electronics association), a ship communication standard, in the future.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.1
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• pp.11-14
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• 2015

WSN (Wireless Sensor Network) based on low-power is one of the core technologies in the ubiquitous society. In this paper, we present a border surveillance and control system in WSN environment. The system consists of static sensor node, mobile sensor node, static gateway, mobile gateway, server and mobile application. Mobile applications are divided into user mode and manager mode. So users monitor border surveillance through mobile phone and get information of border network environment without time and space constraints. In manager mode, for the flexible operation of nodes, manager can update to the software remotely and adjust the position of the mobile node. And also we implement a suitable multi-hop routing protocol for scalable low-power sensor nodes and confirm that the system operates well in WSN environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.459-468
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• 2006

Current routing in sensor networks focuses on finding methods for energy-efficient route setup and reliable relaying of data from the sensors to the sink so that the lifetime of the network is maximized. The existing routing protocols do not have routing tables to determine a path when packets are transferred. A sensor network by a routing table increases a cost of maintaining and updating a path, because sensor nodes have characteristics to be mobile and constrained capacity and resources. This paper proposes a new routing algorithm by broadcasting a bitmap in order to reduce the number of messages transferred when routing paths are established. Each node has a routing table with a bitmap, which contains link information. A bitmap is formed two-dimensional array, which consists of each row and column represented with a bit. The node only updates its own bitmap if it receives a bitmap from another adjacent nodes after the broadcasting. There by, each node has a bitmap with partial links information not total links information on the network. The proposed routing algorithm reduces the number of messages for routing establishment at least 10% compared with the previous algorithms.

• Journal of Korea Multimedia Society
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• v.12 no.1
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• pp.156-167
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• 2009

Computing environment is evolving rapidly to ubiquitous environment. It thus makes people access and utilize any resource on the move and makes location of objects rise to the rank of the most important information. However provision of location information is too restrictive in small environments such as a home or building. In this paper we propose a home entertainment system which supports user mobility based on sensor networks and distributed devices. The proposed system estimates a user location by using signal strength received from Bluetooth ad-hoc networks. This estimated location information can tell which device a user can take advantage of while moving. In order to prove possibility of user mobility support, the system is implemented on our UPnP A/V framework home entertainment system to provide content streaming and the result shows that a provision of service for mobile users could be possible in small ubiquitous computing environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.283-294
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• 2012

Recently increasing usage of smart phones so, the application field of convergence industry between IT technology using smart phone-based mobile communication networks and other industry branches is expanding. In addition, R&D technologies in other fields are applied to smart phone applications effectively in order to develop products and support daily life more convenient. However, it is very hard to control these products and there is no efficient solution for this problem when many people are sent to specific area for big events, such as Biennale, Film Festival, EXPO, and so on. In order to solve this problem, this paper describes a network-based ticket reservation system and its organization using augmented reality on smart phone and mobile communication networks. In particular, we propose a method of designing and developing prototyping system based on smart phone application design technologies, prior to developing real smart phone application.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.442-453
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• 2007

A model-based integrated development tool for the development of USN application programs is proposed in this paper. The proposed tool has been implemented as a plug-in for Eclipse platform. The tool consists of Graphical User Interface, Modeler, Configuration Information Generator, Validity Checker, Source Code Generator and Templates Storage. Developers can implement USN applications from models of sensor networks using the tool. The developer can implement USN applications by automatic generation of execution code of each node in the sensor network after he/she designs a model of the sensor network. The configuration information of each node is automatically generated from the validated USN model. Then, the execution code is automatically generated using the configuration information and the predefined templates. Through the tool of this paper, developers can easily implement valid USN applications even if they do not know the details of low-level information. Also, a large number of application programs can be generated at once because application programs are generated from sensor network model instead of models of applications. Accordingly, the development effort of USN applications will be decreased and developers can consistently construct USN applications from USN models using the proposed tool.

• Journal of Advanced Navigation Technology
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• v.11 no.2
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• pp.154-162
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• 2007

This paper verifies the performance of the wireless-signal map-matching (WSMM) method that is recently proposed to mitigate the effects of non-line-of-sight (NLOS) error in positioning under wireless terrestrial network environments. The WSMM method is the new positioning technology that estimates and compensate the NLOS errors by processing the bulks of anonymous measurements at unknown locations that are collected randomly and automatically. The WSMM method would be advantageous for various configurations of future ubiquitous sensor networks since it is based on the existing network configuration for communication and it requires no additional hardware in base stations and mobile handsets. It is shown that the application of the WSMM concept to the real CDMA pilot strength measurment message (PSMM) actually mitigates the NLOS error effects and improves overall positioning accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.852-855
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• 2010

Based on the rapid development of the computer network technology, the ubiquitous sensor network (USN) was developed to enable us to have access to the communication environment anywhere and anytime without the need for recognizing computers or networks. Moreover, with the increasingly high interest on individual health, the USN technology is being applied to diverse sectors for healthcare and disease prevention. In this paper, a system was designed and implemented using the USN-based RF communication for doctors and nurses who care patients in the hospital to easily measure and control the physiological data on blood pressure and blood sugar. In addition, a database was designed using MS SQL database to store and manage the blood pressure and blood sugar data, which were passively or actively measured from patients. Using the results of this study, the physiological data of patients can be managed in real time and emergency situation can be instantly addressed. It is expected that the healthcare service can be improved and the paradigm of healthcare service environment can be changed.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.737-746
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• 2009

Given the increased interest in ubiquitous computing, wireless sensor network has been researched widely. The localization service which provides the location information of mobile user, is one of important service provided by sensor network. Many methods to obtain the location information of mobile user have been proposed. However, these methods were developed for only one mobile user so that it is hard to extend for multiple mobile users. If multiple mobile users start the localization process concurrently, there could be interference of beacon or ultrasound that each mobile user transmits. In the paper, we propose APL(Adaptive Power Control based Resource Allocation Technique for Efficient Localization Technique), the localization technique for multiple mobile nodes based on adaptive power control in mobile wireless sensor networks. In APL, collision of localization between sensor nodes is prevented by forcing the mobile node to get the permission of localization from anchor nodes. For this, we use RTS(Ready To Send) packet type for localization initiation by mobile node and CTS(Clear To Send) packet type for localization grant by anchor node. NTS(Not To Send) packet type is used to reject localization by anchor node for interference avoidance and STS(Start To Send) for synchronization between 모anchor nodes. At last, the power level of sensor node is controled adaptively to minimize the affected area. The experimental result shows that the number of interference between nodes are increased in proportion to the number of mobile nodes and APL provides efficient localization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1284-1288
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• 2008

Recently, there is increasing the development requirement of middleware and interface for GPS(Global Positioning System), RFID(Radio Frequency IDentification), sensor networks. GPS supports a useful location based service. RFID supports products logistic and distribution services through the identification. A sensor network collects a context information, such as humidity, temperature and atmospheric pressure. This paper implements and verifies a integrated service middleware for supporting efficiently process of sensing data collected from RFID, GPS and sensor network. This middleware have the temporary store function, the redundancy exclusion function, certification function, the classification function and the database storage function. Additionary, this middleware connects with low-level adaptor using socket interface and supports the high-level application services using database connection. Therefore, user can develop easily various many ubiquitous application system using proposed middleware instead of each RFID middleware, GPS middleware and, middleware based on sensor network.