• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.135-138
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• 2009

G-Sensor is being used for controlling motion of smart-phone and robot. G-Sensor can control motion to several direction, because it is composed of X, Y, and Z axis and also can be used on many mobile-phone by using Wi-Fi communication and RS-232C communication on the Bluetooth module. In this research, we suggest the application that realize and develop visual-vehicle-remote-control-system by using mobile-phone with G-Sensor so that drivers can more easily remote control and manage their vehicle with mobile-phone in real-time visual.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.251-252
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• 2009

In smart cold chain, environment monitoring (for example temperature, humidity, and etc) is an important. Especially, because monitoring may be broken on passage, in order to success of cold chain management, it is important that seamless monitoring. To solve this problem, we implement mobile gateway supporting RFID and demonstrate using of RFID middleware emulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1877-1884
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• 2014

Because of the limited power resource, we need a reliable low-power media access control technique suitable for unmaned remote sensor operation condition for the unmanned sensor processor to perform the task in the remote wireless network situation. Therefore CSMA/CA and X-MAC is generally considered to effectively transmit the signal in the low-power wireless network. In this paper, we propose the more efficient low-power LP-MAC Technique which consumes the minimum power and transmits the data faster in condition that the mobile nodes' joining to and leaving from the network which consists of the fixed nodes is fluid. The fixed nodes operate in an asynchronous mode to perform the network self-configuration and transmit data faster to the mobile node which is frequently join and leave the network. When the mobile node leaves the network, the network's operation mode will be synchronous mode to achieve the minimum power consumption, thus the minimum power operation becomes possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1128-1134
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• 2007

Recently, sensor network technology is a highly concerned area due to the expectation of many applications in various fields. The application of sensor network technology to the marine and ocean surveillance and investigation makes the marine environmental research easier since intelligent sensor nodes substitute the human labor work. In ocean sensor network, the localization scheme for the sensor nodes is most essential because all the information without from sensor nodes might be useless unless the positional information of each sensor nodes is provided. In this paper, the localization scheme with mobile beacons in ocean sensor networks is suggested and showed it could be effective for applying to marine circumstances. Even though the previous localization scheme(Ssu's) has advantages that additional hardware is not required for obtaining the information of distance and angle and shows the high accuracy of location and energy efficiency and easy expandability as well, it has also demerits the location error increases as the minimum distance between the absolute positional information become closer. In our works, the improved localization scheme with the presumed area of sensor node using geometric constraints is suggested.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.26-33
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• 2011

In ubiquitous environments that numerous mobile objects exist, the location-based services have risen as an important application field. For efficient location-based services, various techniques with broadcast schemes have been studied. However, they were mainly concerned with the implementation of a broadcast index and did not consider techniques for reducing the size of the entire broadcast data. Therefore, this paper proposes a data distribution broadcast scheme based on sensor networks that considers the mobile patterns of an object in road network environments. In this paper we also propose a road network based sensor clustering technique for the efficiency of the proposed distributed broadcast scheme. In order to show the superiority of the proposed scheme, we compare it with the existing broadcast scheme in various environments.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.151-160
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• 2009

Wireless network solution is used in many area because of free mobility and easy of establishment. Sensors that compose wireless network need protocol that support wireless communication to share information each other. As representative protocol, we currently witnessed IPv6 protocol. However, due to the limitation of sensors's electric power and computing ability, it is inefficient that each sensors use this protocol. In this paper, we designed improved sensor circuit that can heighten energy efficiency in sensor network to solve these problem and composed algorithm that can pare down energy consumption using method to make unnecessary sensor in sleep-mode.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3412-3432
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• 2019

Recent advances in radio frequency (RF) power transfer provide a promising technology to power sensor nodes. Adoption of mobile chargers to replenish the nodes' energy has recently attracted a lot of attention and the mobility assisted energy replenishment provides predictable and sustained power service. In this paper, we study the joint optimization of mobile charging and data gathering in sensor networks. A wireless multi-functional vehicle (WMV) is employed and periodically moves along specified trajectories, charge the sensors and gather the sensed data via one-hop communication. The objective of this paper is to maximize the uplink throughput by optimally allocating the time for the downlink wireless energy transfer by the WMV and the uplink transmissions of different sensors. We consider two scenarios where the WMV moves in a straight line and around a circle. By time discretization, the optimization problem is formulated as a 0-1 programming problem. We obtain the upper and lower bounds of the problem by converting the original 0-1 programming problem into a linear programming problem and then obtain the optimal solution by using branch and bound algorithm. We further prove that the network throughput is independent of the WMV's velocity under certain conditions. Performance of our proposed algorithm is evaluated through extensive simulations. The results validate the correctness of our proposed theorems and demonstrate that our algorithm outperforms two baseline algorithms in achieved throughput under different settings.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.2
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• pp.53-64
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• 2005

Previous secure routing protocols for wireless sensor networks assume that a sink is static. In many cases, however, a sink operated by man or vehicle is moving. A mobile sink creates a lot of technical problems such as reconfiguration of routing path exposure of sink location. and selection of secure access point node, which are not considered by many previous researches. In this paper, we propose a new secure routing scheme for solving such problems using hi-directional hash chain and delegation nodes of grid structure. This scheme provides a secure routing path and prevents attacker from recognizing the location of a mobile sink in sensor networks. This new method reduces the resource requirements compared to the cashed routing schemes. Simulation results also show that the system is secure and efficient enough.

• Journal of KIISE
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• v.42 no.2
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• pp.255-263
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• 2015

The sensor registry system has been developed for instant use and seamless interpretation of sensor data in a heterogeneous sensor network environment. However, the existing sensor registry system cannot provide information for interpretation of the sensor data in situations in which the network is unstable. This limitation causes several problems such as sensor data loss, inaccuracy of processed results, and low service quality. A method to resolve such problems in the aspect of software is presented herein. In other words, an extended sensor registry system is proposed to enable the stable use of sensor information, even under conditions of unstable network connection, by providing sensor information with a mobile device in advance through the user path prediction. The results of experiments and evaluation are also presented. The extended sensor registry system proposed in this paper enhances the stable usability of sensor information as well as improves the quality of sensor-based services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.754-756
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• 2005

RFID(Radio Frequency Identification) is used to describe a system that transmits the identity of an object or person wirelessly using radio waves. RFID is recognized as a key technology of USN(Ubiquitous Sensor Network). ISO/IEC JTC1 and EPCglobal are developing RFID related standards for global supply chain management. RFID is an important solution not only for the supply chain management, but also for USN and future services. Recently, mobile RFID which provide various services using RFID reader in mobile phone, is being standardized in Korea. In this paper, we analyze trends of RFID standardization activities in ISO/IEC JTC1 and EPCglobal and mobile RFID, and propose an convergence scenario of IPv6 and RFID.