• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.319-320
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• 2008

This paper introduces remote-sensing data which can be practically applied for offshore wind resource assessment. Development of offshore wind energy is inevitable for Korea to achieve the national dissemination target of renewable energy, i.e., 5% uptil 2010. However, the only available offshore in-situ measurement, marine buoy data would not represent areal wind characteristics. Consequently, remote-sensing technology has been started to apply to offshore wind resource assessment and is actively developing. Among them, NCAR/NCEP reanalysis dataset, QuikSCAT blended dataset, and offshore wind retrieval from SAR imagery are briefly summarized in this paper.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.101-104
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• 2007

Efficient Query processing and optimization are critical for reducing network traffic and decreasing latency of query when accessing and manipulating sensor data of large-scale sensor networks. Currently it has been studied in sensor database projects. These works have mainly focused on in-network query processing for sensor networks and assumes homogeneous sensor networks, where each sensor network has same hardware and software configuration. In this paper, we present a framework for efficient query processing over heterogeneous sensor networks. Our proposed framework introduces query processing paradigm considering two heterogeneous characteristics of sensor networks: (1) data dissemination approach such as push, pull, and hybrid; (2) query processing capability of sensor networks if they may support in-network aggregation, spatial, periodic and conditional operators. Additionally, we propose multi-query optimization strategies supporting cross-translation between data acquisition query and data stream query to minimize total cost of multiple queries. It has been implemented in WSN middleware, COSMOS, developed by ETRI.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.35-43
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• 2018

In this paper, we propose a grid-based efficient routing protocol for a mobile sink in wireless sensor networks. In the proposed protocol, the network is partitioned into grids and each grid has a grid head. For the efficient routing to a mobile sink, the proposed protocol uses a mobile sink representative node to send the data to a mobile sink and grid heads are used as a mobile sink representative node. Furthermore, the proposed protocol uses nodes in the boundary of the center grid as position storage nodes. The position storage nodes store the position of a mobile sink representative node and provide source nodes with it for data delivery. With these features, the proposed protocol can reduce a lot of overhead to update the position information and improve the delay of data delivery to a mobile sink. The proposed protocol performs better than other protocols in terms of the delay and the energy consumption per node in the performance evaluation.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.159-162
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• 2008

Generally, sensor nodes can be easily compromised and seized by an adversary because sensor nodes are hostile environments after dissemination. An adversary may be various security attacks into the networks using compromised node. False data injection attack using compromised node, it may not only cause false alarms, but also the depletion of the severe amount of energy waste. Dynamic en-route scheme for Filtering False Data Injection (DEF) can detect and drop such forged report during the forwarding process. In this scheme, each forwarding nodes verify reports using a regular probability. In this paper, we propose verification probability adjustment scheme of forwarding nodes though a fuzzy rule-base system for the Dynamic en-route filtering scheme for Filtering False Data Injection in sensor networks. Verification probability determination of forwarding nodes use false traffic rate and distance form source to base station.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.121-123
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• 2017

The widespread dissemination of the green building certification system has led to the ongoing development of information management technologies with the aim to effectively utilize construction product information. Among them, a data crawling technology enables to collect the data conveniently and to manage large volumes of construction product information in Korea and overseas. However, without a standardized classification system, it is difficult to efficiently utilize information, and problems such as an additional work for classifying information or information-sharing errors. Therefore, this study suggests to present a necessity for the standardization of the information classification system through expert interviews, and to compare construction product classification systems in Korea and overseas. This study is expected to present a necessity for the effective management of construction product information and the standardization of information-sharing with regard to various construction certifications.

• Journal of Internet Computing and Services
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• v.17 no.5
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• pp.17-23
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• 2016

Wireless sensor-actuator networks (WSANs) enhance the existing wireless sensor networks (WSNs) by equipping sensor nodes with an actuator. The actuators work with the sensor nodes and perform application-specific operations. The WSAN systems have several applications such as disaster relief, intelligent building, military surveillance, health monitoring, and infrastructure security. These applications require capability of reliable data transfer to act responsively and accurately. Biologically inspired modeling techniques have received considerable attention for achieving robustness, scalability, and adaptability, while retaining individual simplicity. In this paper, an epidemic-inspired algorithm for data dissemination with delay constraints while minimizing energy consumption in WSAN is proposed. The steady states and system stability are analyzed using control theory. Also, simulation results indicate that the proposed scheme provides desirable dissemination delay and energy saving.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1297-1307
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• 2013

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or disseminate useful traffic information to othet vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collision at the link layer due to an excessive number of broadcast packets. To solve broadcast storm problem, we propose an RPB-MACn-based LV-CAST that is a vehicular broadcast algorithm for disseminating safety-related emergency message. The proposed LV-CAST identifies the last node within transmission range by computing the distance extending on 1 hop from the sending node of an emergency message to the next node of receiving node of the emergency message, and the last node only re-broadcasts the emergency message. The performance of LV-CAST is evaluated through simulation and compared with other message dissemination algorithms.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.548-553
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• 2019

Along with advanced vehicle to vehicle (V2V) communication technologies, platooning is regarded as one of the most promising form of autonomous driving solutions in order to increase road capacity. In this paper, we propose a novel V2V transmission scheme for safety message dissemination in platooning. The proposed scheme enhances the efficiency of channel access and multi-vehicle orthogonal frequency division multiple access (OFDMA) transmission by taking advantage of triggered uplink access technique and null data packet feedback report protocol introduced in the sixth generation WLAN standard, IEEE 802.11ax. The simulation results prove that the proposed scheme outperforms the conventional IEEE 802.11 transmission scheme throughout all measured vehicle density range.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.168-177
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• 2008

The code propagation is one of the most important technic for software update in wireless sensor networks. This paper presents a new scheme for code propagation using network coding. The proposed code propagation method roughly shows 20$\sim$25% performance improvement according to network environments in terms of the number of data exchange compared with the previously proposed pipelining scheme. As a result, we can efficiently perform the software update from the viewpoint of speed, energy, and network congestion when the proposed code propagation system is applied. In addition, the proposed system solves the overhearing problems of network coding such as the loss of original messages and decoding error using the predefined message. Therefore, our system allows a software update system to exchange reliable data in wireless sensor networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9B
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• pp.847-856
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• 2009

In geographic routing for wireless sensor networks, sources need the location of sinks destined for delivering their data packets. Most of the existing geographic routing protocols merely assume that the sources can get the locations of sinks by some location service. How source nodes find out the location of sinks is not easy. In this paper, we propose a sink location dissemination scheme in geographic routing for wireless sensor networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. Then the source can send data packet to the sink by geographic routing. How to guarantee that these two paths have at least one crossing point in any irregular profile of sensor network is the challenge of this paper Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.