• The Journal of the Korea institute of electronic communication sciences
• /
• v.4 no.3
• /
• pp.243-246
• /
• 2009

A cluster-based routing with a hierachical structure for continuous query stream ubiquitous sensor network is proposed in this paper. the proposed method realizes high energy-efficiency by using a head-set instead of head for transmitting node-messages to a base station. By using head-set, the method make network lifetime increased.

• Journal of Korean Society of Forest Science
• /
• v.96 no.5
• /
• pp.510-514
• /
• 2007

The main purpose of this study was to develop Mountain Search and Rescue System for enhancing search and rescue operations in the mountains. This study also focused on presenting an alternative to using a cellular phone for requesting rescue due to their unreliability in remote areas. This system is designed to help in the search and rescue of people in emergency situations in the mountains. It is composed of buzzer sensors, environmental information sensors, and a statistical analysis program. A key feature of this system is that it does not require an infrastructure of internet or CDMA networks for its operation in the mountains. The measure for the study was conducted by using a zigbee protocol analyzer, RF module and 433MHz Helical antenna to analyze the rate of data reception in relation to the distance between nodes. This system is applicable to mountains provided the distance between nodes is over 100 m and under 150 m.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.4 no.3
• /
• pp.9-18
• /
• 2008

Mobile devices do not need the fixed network infrastructure in ad-hoc network, these devices communicate each other through the distributed control. Accordingly, mobile devices can discover several services using dynamic searching method and provide safely public ownership of these services. Ad-hoc network needs the distributed control and topology of dynamic network because the limited power for processing and network communication. This paper is devoted to provide the secure protocol that provides efficient services discovery using SDP(Service Discovery Protocol) and considers the security requirements. Proposed protocol provides the distributed control based on PKI without central server, the discovery of trusted service, secure telecommunication, the identification among mobile devices, and service access control by user authority.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.6
• /
• pp.131-136
• /
• 2010

Reducing the energy consumed by sensor node is a critical issue in wireless sensor networks. In particular, energy in each sensor node is too limited to waste on overhearing of packets that are not relevant. In this paper, we propose a wakeup scheme to reduce overhearing energy through the wakeup time difference between neighboring nodes. Other research papers on wakeup schemes usually focus on decreasing the latency. We propose a technique to reduce wasted energy for overhearing using the wakeup scheme. Simulation results indicate that our proposed wakeup scheme improves the sensor network lifetime.

• Journal of Biomedical Engineering Research
• /
• v.29 no.6
• /
• pp.457-465
• /
• 2008

HL7(Health Level 7) is a standard for exchanging medical and healthcare data among different medical information systems. As the ubiquitous era is coming, in addition to text and imaging information, a new type of data, i.e., streaming sensor data appear. Since the HL7 is not covering the interfaces among the devices that produces sensor data, it is expected that sooner or later the HL7 needs to include the biomedical sensors and sensor networks. The IEEE 1451 is a family of standards that deals with the sensors, transducers including sensors and actuators, and various wired or wireless sensor networks. In this paper, we consider the possibility of interoperability between the IEEE 1451 and HL7. After we propose a format of messages in HL7 to include the IEEE 1451 TEDS, we present some preliminary results that show the possibility of integrating the two standards.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.6
• /
• pp.1113-1119
• /
• 2008

In IP-USN for replacing the sensor network based on Zigbee by IP-based it, routing and the address assignment technique for sensor node are important focuses. But, there is a weak point in existing hierarchical routings. It is that all paths must be searched because the end node isn't considered. And the end node based muting is not sufficient in the mobile sensor network environment because it supports the only simple-path-search. Hereupon, this thesis suggests ComHRP(Complement HRP) that have the only merits of existing methods. The address assignment technique and search method are also proposed. ComHRP simplifies the organization of sensor networks and reduces network complexity. Also, It can efficiently deal with restructuring networks for the unpredictable ubiquitous sensor network feature.

• Journal of Internet Computing and Services
• /
• v.9 no.1
• /
• pp.79-90
• /
• 2008

In the ubiquitous environment sensor network technologies have advanced for collecting information of the environment. With the rapid growth of sensor network technology, it is necessary and important to share the collected sensor data with a large base of diverse users. In order to provide dissemination of sensor data, we design an information dissemination system using an independent disseminator between provider and consumer. This paper describes how we designed the information dissemination system using one of the possible dissemination patterns for sensor networks, and an efficient matching algorithm called CGIM (Classed Grouping Index Matching) which employs a dynamic re-grouping scheme.

• Journal of Korea Society of Industrial Information Systems
• /
• v.16 no.2
• /
• pp.85-97
• /
• 2011

Wireless sensor networks have emerged as one of the key enabling technologies for ubiquitous computing since wireless intelligent sensor nodes connected by short range communication media serve as a smart intermediary between physical objects and people in ubiquitous computing environment. We recognize the wireless sensor network as a massively distributed and deeply embedded system. Such systems require concurrent and asynchronous event handling as a distributed system and resource-consciousness as an embedded system. Since the operating environment and architecture of wireless sensor networks, with the seemingly conflicting requirements, poses unique design challenges and constraints to developers, we propose a very new operating system for sensor nodes based on finite state machine. In this paper, we clarify the design goals reflected from the characteristics of sensor networks, and then present the heart of the design and implementation of a compact and efficient state-driven operating system, SenOS. We describe how SenOS can operate in an extremely resource constrained sensor node while providing the required reactivity and dynamic reconfigurability with low update cost. We also compare our experimental results after executing some benchmark programs on SenOS with those on TinyOS.

• The Journal of the Korea Contents Association
• /
• v.7 no.2
• /
• pp.51-62
• /
• 2007

Recently microcontrollers are being used in sensor networks to handle sophisticated control and monitoring activities. As applications become more sophisticated, their design and development processes become more complex which consequently necessitates the use of an operating system to manage the complexity and provide an abstraction for portability of code. This paper presents a Low-power real-time operating system, called UbiFOS-USN, designed for sensor networks. We present some of the features that make UbiFOS-USN appropriate especially for small, low-cost microcontrollers typically found in sensor networks. Through experimental results, we show that UbiFOS-USN is quite efficient for a sensor network, both in terms of system performance and memory requirement.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.770-775
• /
• 2009

Along with the advance of USN technology in a human-oriented informatization society these days, society is quickly changing into a ubiquitous computing society in which information even between objects can be organically combined and utilized. In order to successfully build such a ubiquitous computing society, it is indispensable to have core USN technologies such as USN sensor nodes, sensor networks, USN middleware, and USN applied services that efficiently manage sensing information collected from sensor nodes, and support the abstraction function for the composition of sensor networks. In order to process the transmission event of sensing values that are generated from various USN terminal devices, this study designs a process that performs the abstraction of data for the efficient process of diverse sensing values transferred from USN and RFID terminal devices.