Hyeon Park

Reliable and real-time data dissemination in wireless sensor networks

In wireless sensor networks, both real time and reliable transmission are the big research challenge. But current approaches in these research fields have not been well explored because there are so many restrictions on respective sensor node. In this paper, we propose a new reliable real time routing protocol in sensor networks. For real time delivery, we introduce a time-based forwarding scheme in wireless sensor networks. In addition, reliable transmission is accomplished by multiple transmissions based on link quality in such a distributed way. Finally, simulation results are presented to demonstrate the proposed scheme meets real time and reliable transmission in wireless sensor networks.

Redundancy reduction protocol with sensing coverage assurance in distributed wireless sensor networks

In large scale applications like military surveillance, sensing coverage is essential for target detection and optimization of power consumption is important for lifetime extension of the network. In battle field, nodes are deployed randomly which results some places empty and some places dense. To assure the sensing coverage for the whole area of interest, sensors are deployed several times which represents random distribution with dense node deployment. This dense sensor deployment shows redundancy. These redundant traffics result collisions, packet losses and retransmissions. Consequently it consumes more energy and decreases the lifetime of the network. In order to use this dense sensor network efficiently to increase the lifetime of the network, it is necessary to find out a set of small number of working nodes that can cover the region of interest and reduce redundancy. In this paper, we propose a new energy efficient protocol where each node in the network takes decision to turn on or turn off in a distributed manner that results a set of small number of active nodes throughout lifetime of the network and covers sensing area of interest for target detection. It reduces redundancy, power consumption and increase the lifetime of a network. In this protocol, nodes balance their energy by going to working state based on their residual energy to keep the nodes alive to assure the coverage throughout the lifetime. The simulation results of this protocol shows that throughout network lifetime the coverage is preserved in a range from 84% to 100% and about a constant number of nodes are working.

Performance evaluation of routing protocols for wireless sensor networks in military scenarios

Surveillance and reconnaissance applications in wireless sensor networks (WSNs) are primarily intended to detect, identify and track adjacent hostile targets in military environments. These applications require the high reliability in acquiring the precise information on the enemy and they pursue energy-efficiency to ensure the longevity of their mission. Until now, although a lot of routing protocols have been proposed to route packets towards destinations reliably and efficiently, there exists no routing protocol which is designed for such applications only. In this work, we therefore investigate the applicability of existing WSN routing protocols (BVR, MINT, GRAB and ZBR) to military sensor networks through simulation study regarding the four performance metrics: packet delivery ratio, average end-to-end delay, control packet overhead and the average amount of energy consumption.

Data traffic based route selection for real-time data delivery in wireless sensor networks

Surveillance and reconnaissance applications such as military in wireless sensor networks require timely transfer of important data (i.e., the detection of enemy troops and vehicles) to a remote base station or sink node. Unfortunately, picking up the reliable routing path to deliver the data in realtime is difficult because of various interferences, often environmental changes, and so on. Thus, routing protocols based on the link quality to select the routing path are affected by those kinds of factors. In this paper, we propose a reliable routing mechanism that provides real-time transfer of the important data. In other words, we provide the weighted link quality metric that reflect the TX/RX traffic flow to select the reliable route over the routing path. Moreover, we also provide a cross-layer routing protocol design in order to reduce the data queue processing time and to send out the priority data at both network and MAC layer.

PaaS offering for the big data analysis of each individual APC

Application developers who work in the agricultural sector usually develop the application SW, for example, ERP (Enterprise Resource Planning), for farm product companies such as APCs (Agricultural Product Processing Center). However, they are faced with some problems to meet their requirements according to increasing numbers of APC. Each individual APC wants to get the accurate result of forecasting about the supply and demand of the agriculture products using its own data, the crop yield and price. Thus, the appropriate development environment and analysis model for each individual APC must be considered. This paper aims to offer the platform service, PaaS, for the application developer. It facilitates the use of various development environments, which enable to protect the APC own information and to easily develop applications for big data analysis. We implemented PaaS platform for the agriculture sector using VM (Virtual Machine) instances and API (Application Programming Interface) components.

Hybrid Clustering Framework for Multi-dimensional Array Data

As the satellite imagery containing multi-dimensional array data is currently used for analysis of various applications, the frameworks to analyze that sort of scientific data have been introduced. To process the scientific data like the satellite imagery there are some restrictions: for the analysis of large-scale data the aggregated data would be stored in specified data formats, for the time-series analysis of the huge size the specified file system would be needed as the data is rapidly increased, and so on. Although Hadoop framework which is big data computing platform is popular to process the big data it is not feasible to handle the scientific data. It does not support to process the data in different scientific formats. On the other hand, though SciDB is the data management system to mainly process large-scale array data, it is not appropriate to analyze the scalable data of the time series. In this paper, we propose hybrid clustering framework, which is to process the scientific data composed of the multidimensional arrays with time series. The proposed framework would address the issues to provide the framework both processing array-based scientific data and handling ever-increasing data at the same time.

Design and Deployment of Testbed for Experimental Sensor Network Research

This paper presents the Ubiquitous Sensor Network (USN) testbed, which is deployed at Electronics and Telecommunications Research Institute (ETRI), in Republic of Korea. USN testbed is a state-of-the-art sensor network experimental facility composed of various components. It includes heterogeneous sensor nodes with variety of sensing module ranging from ultra-low power to high performance hardware platforms, a scalable and reliable Ethernet based wired backplane network to program, interact with and receive/send data from/to the sensor nodes, an easily extendable application software suite which glues and drive everything in a user friendly manner, and an indoor and outdoor deployment space offering various environmental characteristics. We also included two case studies where researchers have put USN testbed into practice for experimental evaluation of algorithms and networking protocols. The case studies cover routing and clustering protocol in wireless sensor networks.

Design of home sensor service platform using sensor network middleware

This paper proposes a home sensing service platform which can collect and aggregate sensing values from various sensing devices in home. It can manage heterogeneous sensor network and provide interoperability with UPnP middleware as device service functionalities. 1

New link estimation for reliability in wireless sensor networks

A low-rate, short-range wireless radio communication naturally requires complementary functions to achieve reliability in wireless sensor networks. The well-known protocol is MINT, which is deployed in TinyOS. However, link quality metric like packet reception rates employed in MINT causes huge number of path changes because packet reception rates is drastically affected by many several parameters. Thus, unnecessary delay and packet loss are inevitably brought. In this paper, we propose a new metric for link estimation, which works with MINT to improve the performance. It is designed to take cross-layered principle in wireless sensor networks as well as several network environments into account. Simulation results reveal that current scheme for link quality is not enough to estimate the quality on link. In addition, more reliable links are chosen so less frequent procedures for parent selection are invoked in the proposed scheme.

Integrated Multi Mobile Object Scheme for Ubiquitous Sensor Network

By Configuration of the sensor node that utilizes the wireless service in constructing the network and collecting the data, the USN has been researched on the technology to be utilized as the various services such as disaster alarm, healthcare and military defense. Since the low power plan for extending the lifetime of the battery is considered to be important for the USN, the various USN simulators that design and verify the efficient packets were developed. In this paper, to overcome the limitations of the existing simulators that is limited to the packet, protocol and network model verification, to propose the CROWD that includes the mobile objects. While the existing simulators had operated in the form of being dependent on the event of voluntary generating within the terminal node, the CROWD alters the positioning coordinates for the mobile objects to react to the sensor node and provide the similar environment with the actual USN. Furthermore, CROWD verifies the sensor detection rate by the deployment and the energy efficiency and sensor positioning method according to the measured lifetime of the overall sensor node and the packet transfer route.