• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.7A
• /
• pp.706-714
• /
• 2010

In wireless sensor networks, real-time data delivery schemes typically achieve a desired delivery speed by performing one-hop lookahead. Recently, to reduce the deadline miss ratio against the desired delivery speed, a study has proposed a real-time routing protocol based on proactively performing two-hop lookahead. However, the study might cause heavy message exchange overhead and high computing complexity to carry out obtainment of two-hop neighborhood speed information in the entire sensor nodes whether data are delivered or not. Moreover, although multi-hop lookahead provides the least deadline miss ratio, due to the restriction from the overhead and the complexity, the recent study merely adopts the two-hop lookahead manner. In this paper, we propose a novel real-time routing protocol that adopts on-demand neighborhood multi-hop information obtainments only around data forwarding paths. Simulation results prove that the proposed routing protocol offers better performances with respect to deadline miss ratio, total communication costs, energy efficiency, and network lifetime.

• Journal of the Korea Society for Simulation
• /
• v.17 no.3
• /
• pp.95-105
• /
• 2008

In this paper, we propose the DAMMC(Distributed Authentication Model using Multi-level Cluster) for wireless sensor networks. The proposed model is that one cluster header in m-layer has a role of CA(Certificate Authority) but it just authenticates sensor nodes in lower layer for providing an efficient authentication without authenticating overhead among clusters. In here, the m-layer for authentication can be properly predefined by user in consideration of various network environments. And also, the DAMMC uses certificates based on the threshold cryptography scheme for more reliable configuration of WSN. Experimental results show that the cost of generation and reconfiguration certification are decreased but the security performance are increased compared to the existing method.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.6 no.2
• /
• pp.161-166
• /
• 2006

Localization of mobile agent within a sensing network is a fundamental requirement for many applications, using networked 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, This paper describes a networked sensor-based navigation method in an indoor environment for an autonomous mobile robot which can navigate and avoid obstacle. In this method, the self-localization of the robot is done with a model-based vision system using networked sensors, and nonstop navigation is realized by a Kalman filter-based STSF(Space and Time Sensor Fusion) method. Stationary obstacles and moving obstacles are avoided with networked sensor data such as CCD camera and sonar ring. We will report on experiments in a hallway using the Pioneer-DX robot. In addition to that, the localization has inevitable uncertainties in the features and in the robot position estimation. Kalman filter scheme is used for the estimation of the mobile robot localization. And Extensive experiments with a robot and a sensor network confirm the validity of the approach.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.5
• /
• pp.809-816
• /
• 2024

In a Wireless Sensor Network (WSN) environment, where numerous small sensors are arranged in a certain space to form a wireless network, each sensor has limited battery power. Therefore, the lifetime of each sensor node is directly related to the network's lifetime, necessitating efficient routing to maximize the network's lifespan. This study proposes a routing protocol based on PEGASIS, a representative energy-efficient routing protocol in WSN environments. The proposed protocol categorizes nodes into groups based on their distance from the sink node, forms multiple chains within each group, and selects the leader node for each group by comparing the remaining energy levels. The proposed method ensures that each group's leader node is the one with the highest energy within that group, which has been shown to increase the network's lifespan compared to the traditional PEGASIS method.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.289-291
• /
• 2005

Even though a lot of routing algorithms have been proposed, an omnipotent algorithm of routing technique, which has optimal efficiency, does not exist. Therefore, A routing algorithm in a sensor network is an application oriented; the best effective routing algorithm depends on which application it is used to. In this paper, the routing algorithm is proposed for the purpose of monitoring a movement of Assets in office. This Paper proposes a new multi-hop routing algorithm, that is, RSS(Received Signal Strength) value which was used in a localization of sensor network is applied to routing algorithm.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.162-164
• /
• 2006

This whitepaper is a research about the sensor network technology which enhance the performance of the blood management system. The problem of measuring and monitoring the real time temperature of a every point in a limited environment let us to develop a system which is able to monitor the temperature of a remote area using multi-hop networking technology. This whitepaper propose the error correction technologies, which were used to eliminate problems that might occur during real tests of the system.

• Journal of Advanced Navigation Technology
• /
• v.14 no.6
• /
• pp.984-989
• /
• 2010

In this paper, parallel programming technique by using Java Thread is introduced so as to develop parallel design tool to analyze the small micro flow sensor. To estimate computing time for Thread-level parallelism, the performances of two experimental models for potential problem subject to Thermal transfer equation are examined. As a result, if the number of network PC is increase, computing time for parallelism on network environment is enhanced to be almost n times. The micro sensor design tool based on distributed computing can be utilized to analyze a large scale problem.

• The KIPS Transactions:PartC
• /
• v.18C no.3
• /
• pp.167-178
• /
• 2011

As the growth of ubiquitous services, various types of ad hoc networks have emerged. In particular, wireless sensor networks (WSN) and mobile ad hoc networks (MANET) are widely known ad hoc networks, but there are also other kinds of wireless ad hoc networks in which the characteristics of the aforementioned two network types are mixed together. This paper proposes a variant of the Low Energy Adaptive Cluster Hierarchy (LEACH) routing protocol modified to be suitable in such a combined network environment. That is, the proposed routing protocol provides node detection and route discovery/maintenance in a network with a large number of mobile sensor nodes, while preserving node mobility, network connectivity, and energy efficiency. The proposed routing protocol is implemented with a multi-hop multi-path algorithm, a topology reconfiguration technique using node movement estimation and vibration sensors, and an efficient path selection and data transmission technique for a great many moving nodes. In the experiments, the performance of the proposed protocol is demonstrated by comparing it to the conventional LEACH protocol.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.363-364
• /
• 2008

Localization algorithms are required for indoor sensor network applications. In this paper, we introduce an efficient algorithm for low complexity and high accuracy, termed multi-internal division localization(MID), which emphasizes simple refinement and low system-load for low-cost and low-rate wireless sensors. We inspect MID algorithm through MATLAB simulation.

• Journal of Industrial Technology
• /
• v.34
• /
• pp.39-43
• /
• 2014

This paper represents a highly porous MWCNT film electrode with interconnected open pores and demonstrated the possibility of using an MWCNT network film as the top electrode for polyimide capacitive humidity sensors. Polyimide humidity sensors with MWCNT electrodes exhibited about 6 times faster response than equivalent Cr electrode sensors. This result may be due to their percolated pore structures, which make water molecules accessible to all polyimide surfaces. The much faster response times of MWCNT electrode sensors is attributed to the percolated pore network, which allows more water molecules to be accessible to polyimide surfaces.