• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1138-1143
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• 2006

Sensor deployment is an important issue in the mobile wireless sensor network. In this paper, we propose a deployment algorithm for mobile sensor network to spread out mobile sensor nodes widely as well as regularly. Since the proposed algorithm uses tree topology in deploying the sensor nodes, calculating power as well as spreading speed can be reduced compare to other deployment algorithms. The performance of the proposed algorithm is simulated using NS-2 simulator and demonstrated.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.225-228
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• 2005

A context-aware services platform supporting mobile agents consists of sensor nodes and a sensor coordinator. Sensor nodes collect environmental information and transmit the collected information to the sensor coordinator through wireless sensor networks. The sensor coordinator passes the information to the context-aware service module, and the mobile agent. The context-aware service module or the mobile agent performs services suitable for a user's situation based on the environmental information and a service actuation message is delivered to an actuation node through the sensor coordinator. In this paper, we present a context-aware services platform structure employed in our project, and describe context-aware services platform interfaces with a context-aware service module and mobile agents.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.281-285
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• 2009

Mobile robot has various sensors for describing the external world. The ultrasonic sensor widely applied to the most mobile robot to detect the obstacle and environment owing to low cost, its easy to use. However, ultrasonic sensor has major problems: the uncertainty information of sensor, false readings caused by specular reflection, multi path effect, low angular resolution and sensitivity to changes in temperature and humidity. This paper describes a sensor system for map building of mobile robot. It was made of low cost PSD (Position Sensitive Detector) sensor array and high speed RISC MPU. PSD sensor is cost effective and light weighting but its output signal has many noises. We propose heuristic S/W filter to effectively remove these noises. The developed map building sensor system was equipped on a mobile robot and was compared with ultrasonic sensor through field test.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.791-795
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• 2006

하이브리드 센서 네트워크에서 static sensor node들이 초기 배치된 후, coverage-hole을 결정하여, hole을 커버할 mobile sensor node들의 필요한 수 및 위치를 결정하고 배치하는 연구는 상당한 수준에 이르렀다. 그러나 mobile sensor node들을 호출하고 배치하는데 너무 많은 에너지를 소모하고 있다. 본 논문에서는 coverage-hole에서 mobile sensor node들을 호출하기 전에 mobile sensor node들을 최대한 coverage-hole에 가깝게 배치하여, 호출하는데 소요되는 에너지를 획기적으로 절감하였다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.99-105
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• 2016

The active rule system is a key element of the rule-based mobile agent middleware system for activeness and autonomy of the sensor network. The rule manager, which is the main components of active rule based mobile agent framework and active rule system, performs the control and management of the rule-related processes. In this paper, we design and implement the roles and functions of the rule manager in detail. The proposed rule manager plays an important role in the sensor network environment. The sensor data server loads the active rule on the mobile agent by the rule manager according to the situations, and the mobile agent migrates to the destination node and performs the designated action. This active rule-based mobile agent middleware system presents the usefulness for the various sensor network applications. Through the rule execution experiment using the rule-based mobile agent, we show the adaptability and applicability of rule-based mobile agent middleware system to the dynamic environmental changes in sensor networks.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.423-423
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• 2000

This paper proposes an effective algorithm for following a wall by an autonomous mobile robot with sonar sensors and infrared sensors in an indoor environment. The proposed method uses deadreckoning to estimate the current position and orientation of a mobile robot. Sonar sensor data are used to estimate shape and position of wall using proposed algorithm. Infrared sensor data are used as assistant when sonar sensor data is uncertain. Simulation results using mobile robot show that the proposed algorithm is proper for the following wall.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.204-216
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• 2010

Since Sensor nodes around a fixed sink have huge concentrated network traffic, the battery consumption of them is increased extremely. Therefore the lifetime of sensor networks is limited because of huge battery consumption. To address this problem, a mobile sink has been studied for load distribution among sensor nodes. Since a mobile sink changes its location in sensor networks continuously, the mobile sink has time limits to communicate with each sensor node and unstable signal strength from each sensor node. Therefore, a fair and stable data collection method between a mobile sink and sensor nodes is necessary in this environment. When some sensor nodes are not able to send data to the mobile sink, a real-time application in sensor networks cannot be provided. In this paper, the new scheduling method, FQMS (Fair Queuing for Mobile Sink), is proposed for fair and stable data collection for mobile sinks in sensor networks. The FQMS guarantees balanced data collecting between sensor nodes for a mobile sink. In out experiments, the FQMS receives more packets from sensor nodes than legacy scheduling methods and provides fair data collection, because moving speed of a mobile sink, distance between a mobile sink and sensor nodes and the number of sensor nodes are considered.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.525-529
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• 2009

On the limited urban area meteorological data are hard to be collected because of the cost problem. The facilities collecting the data require high installment cost. Recently, the sensor network technique comes to the fore as a solution. Furthermore a mobile phone also becomes to be recognized as a sensor. This paper studies an application to service the meteorological map using mobile phone sensor. A design results for system implementation are introduced in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2529-2547
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• 2012

In this paper, we use a quadrotor-based mobile sink to gather sensor data from the terrestrial deployed wireless sensor network. By analyzing the flight features of the mobile sink node, we theoretically study the flight constraints of height, velocity, and trajectory of the mobile sink node so as to communicate with the terrestrial wireless sensor network. Moreover, we analyze the data amount which the mobile sink can send when it satisfies these flight constraints. Based on these analysis results, we propose a data acquisition approach for the mobile sink node, which is discussed detailed in terms of network performance such as the transmission delay, packet loss rate, sojourning time and mobile trajectory when given the flying speed and height of the mobile sink node. Extensive simulation results validate the efficiency of the proposed scheme.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.4
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• pp.167-174
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• 2018

Presently, the exploration of an unknown environment is an important task for the development of mobile robots and mobile robots are navigated by means of a number of methods, using navigating systems such as the sonar-sensing system or the visual-sensing system. To fully utilize the strengths of both the sonar and visual sensing systems, In mobile robotics, multi-sensor data fusion(MSDF) became useful method for navigation and collision avoiding. Moreover, their applicability for map building and navigation has exploited in recent years. In this paper, as the preliminary step for developing a multi-purpose autonomous carrier mobile robot to transport trolleys or heavy goods and serve as robotic nursing assistant in hospital wards. The aim of this paper is to present the use of multi-sensor data fusion such as ultrasonic sensor, IR sensor for mobile robot to navigate, and presents an experimental mobile robot designed to operate autonomously within indoor environments. Simulation results with a mobile robot will demonstrate the effectiveness of the discussed methods.