• Proceedings of the Korean Information Science Society Conference
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• 2008.06a
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• pp.179-180
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• 2008

• Proceedings of the Korean Information Science Society Conference
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• 2007.06a
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• pp.119-120
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• 2007

센서 네트워크는 온도, 습도, 무게, 화학물질 밀도 등과 같이 공간적 시간적 상관관계가 있는 데이터를 실시간으로 수집하는 응용에 적용될 수 있다. 본 논문에서는 1차원과 2차원의 센서 네트워크에서 센서 노드의 작동 확률을 고려한 경우에 데이터 왜곡을 모델링하는 수식을 제시하고 데이터 왜곡을 최소화할 수 있는 최적의 노드 개수에 대한 새로운 계산 결과를 제시한다 계산 결과는 최적의 노드 개수는 패킷의 hop 지연과 관련이 있다는 것을 보여주었다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.257-257
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• 2004

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.833-834
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• 2006

In this paper, It is proposed collecting, processing, and learning of data with PIC16F877 and Acode 300[3], constructing database in PC. The PIC16F877 microcontroller nodes are the radio sensor and the DC motor controller. The PC of flexible factory level construct the data-table for object-oriented optimal environment control. The DC Motor control command is decision with back-propagation.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.107-112
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• 2013

In this paper, we discuss a 3-dimensional localization sensor node using EM waves (Electromagnetic waves) with RSSI (Received Signal Strength Indicator). Generally EM waves cannot be used in underwater environment, because the signal is highly attenuated by the water medium according to the distance. Although the signal quickly reduces in underwater, the reducing tendency is very clear and uniform. Hence EM waves have possibility as underwater distance sensors. The authors have verified the possibility by theory and several experiments, and developed calibration methods in case of linear and planer environment. For 3-dimensional localization in underwater, it must be known antenna's radiation pattern property in electric plane(called E-plane). In this paper, we proceed experiments to verify attenuation tendency with z axis movement, PLF (Polarization Loss Factor) and ILF (Inclination Loss Factor) with its theoretical approach.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.277-277
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• 2009

In this paper, PMPG (Piezoelectric Micro Power Generator) was investigated by ANSYS FEA (Finite Element Analysis) to decrease operating frequency and improve out power. The micro power generator was designed to convert ambient vibration energy to electrical power as a ZnO piezoelectric material. To find optimal model in low vibration ambient, the shape of power generator was changed with different membrane width, thickness, length, and proof mass size. Used the ANSYS modal analysis, bending mode and stress distribution of optimal model were analyzed. Also, the displacement with the frequency range was analyzed by harmonic analysis. From the simulation results, the resonance frequency of optimal model is about 373 Hz and confirmed the possibility of ZnO micro power generator for wireless sensor node applications.

• Journal of IKEEE
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• v.13 no.2
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• pp.108-117
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• 2009

In recent years, one of alternatives for constructing RFID networks that provide mobile services is using wireless sensor networks (WSN) to enhance network capacity, utility and scalability. Due to absence of compatible reader anti-collision control and channel capture phenomenon, the medium access control protocols as used in the RFID networks lead to reader collision and starvation problem. In this paper, we develop a MAC protocol which is called Enhanced Collision Avoidance MAC (ECO) to avoid reader to reader collisions in an integrated RFID network. ECO is a CSMA-based MAC protocol, and operates on integrated nodes which consist of a RFID reader and a mote. Performance evaluation shows superior results to pure-CSMA protocols under dense deployment environments, both in number of failures and in throughput.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.1946-1958
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• 2011

Wireless Sensor Network (WSN) is made up of a number of sensor nodes and base stations. Traffic flow in WSN appears self-similar due to its data delivery process, and this impacts queue length greatly and makes queuing delay worse. Active queue management can be designed to improve QoS performance for WSN. In this paper, we propose self-similar traffic rate estimating algorithm named Power-Law Moving Averaging (PLMA) to regulate packet marking probability. This algorithm improves the availability of the rate estimation algorithm under the self-similar traffic condition. Then, we propose an adaptive Proportional Integral algorithm (SSPI) based on the estimation of the Self-Similar traffic rate by PLMA. Simulation results show that SSPI can achieve lower queue length jitter and smaller setting time than PI.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1228-1235
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• 2012

In this Paper, we propose an energy efficient localization technique based on WUSB (Wireless USB) over WBAN (Wireless Body Area Networks) protocol required for Wearable Computer systems. For this purpose, the proposed localization algorithm minimizes power consumption and estimates location without range information. It is executed independently on the basis of WUSB over WBAN protocol at each sensor node comprising peripherals of a wearable computer system. And it minimizes power consumption by estimating locations of sensor nodes with range-free method fast.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.407-409
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• 2011

Wireless Sensor Networks "WSN" can be implemented in a wide range of applications. Some of these have unpredictable behavior, such as disaster or intrusion monitoring. Sudden large bursting amounts of data can increase traffic and degrade the WSN's performance as well as energy resources. In this work we propose an adjustment of radio transmission range where more or less nodes can be part of the neighborhood area and collaborate in retransmission. As simulation results prove, such adjustment based on traffic can benefit to balance network lifetime.