• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1935-1940
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• 2009

One of the key technical challenges of wireless sensor network (WSN) is location management of sensor nodes. Typical node location management methods use GPS, ultrasonic sensors or RSSI. In this paper we propose a new location management method which adopts regression analysis of RSSI measurement to improve the accuracy of sensor node position estimation. We also evaluated the performance of proposed method by comparing the experimental results with existing scheme. According to the results, our proposed method, LM-RAR, shows better accuracy than existing location management scheme using RSSI and Friis' equation.

• Smart Structures and Systems
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• v.3 no.3
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• pp.357-372
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• 2007

Parametric density concept is proposed for a long-range pipeline health monitoring. This concept is designed to obtain the attenuation of ultrasonic guided waves propagating in underwater pipelines without complicated calculation of attenuation dispersion curves. For the study, three different pipe materials such as aluminum, cast iron, and steel are considered, ten different transporting fluids are assumed, and four different geometric pipe dimensions are adopted. It is shown that the attenuation values based on the parametric density concept reasonably match with the attenuation values obtained from dispersion curves; hence, its efficiency is proved. With this concept, field engineers or inspectors associated with long-range pipeline health monitoring would take the advantage of easier capturing wave attenuation value, which is a critical variable to decide sensor location or sensors interval.

• Journal of the Korea Computer Industry Society
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• v.5 no.1
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• pp.177-182
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• 2004

In sonar sensor design impedance matching design to each sensor affects the whole weighting circuit characteristic very much. But there are many examples that it is made by hands or very simple modeling designs. So these design works make trial and error because it is the limitation of flexible correspondence to the many sensors and follows many errors. This study explains organizations and skills in the sensor modeling package design program with real sonar sensor characteristic measure as the first step in impedance matching design.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.106-112
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• 1993

A new model for the construction of a sonar map in a specular environment has been developed ad implemented. In a real world where most of the object surfaces are specular ones, a sonar sensor suffers from a multipath effect which results in a wrong interpretation of an objects's location. To reduce this effect and hence to construct a reliable map of a robot's surroundings, a probabilistic approach based on Bayesian reasoning is adopted to both evaluation of object orientations and estimation of an occupancy probability of a cell by an object. The usefulness of this approach is illustrated with the results produced by our mobile robot equipped with ultrasonic sensors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.780-787
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• 2014

This paper experimentally deals with the vibration characteristics of flat ring transducers used for ultrasonic sensors and actuators. Radial vibration mode, which is the fundamental mode of a thin piezoelectric transducer, was measured by a laser in-plane vibrometer. An impedance analyzer was used to measure natural frequencies. The results measured by experiments verified theoretical predictions. The vibration characteristics of ring transducers were identified according to the outer diameter size. The shape of the fundamental mode is almost uniform but slightly decreases from the inner to the outer circumferential surfaces. The natural frequency of the fundamental mode decreases as the outer diameter increases. It appears that the ring type transducer is suitable to excite uniformly distributed vibration on a flat surface.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.938-941
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• 1992

This paper presents an acoustic emission(AE) technique using ultrasonic sensors to diagonize power transformers. Conventional methods detect and measure the electrical signal of the partial discharge(PD) of transformers in operation. The proposed techniques measures the acoustic signal generated by the partial discharge, and counts the number of the waveforms above a threshold to diagonize transformers. Experiments showed that the proposed method improved diagonosis capability over the conventional PD method.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.83-85
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• 2005

Exploration involving mapping and localization in an unknown environment is an important task in mobile robots. For this, robot must be able to build a reliable map of surroundings and to estimate the position of it. In this paper, we developed technique for gird-based localization of a mobile robot with ultrasonic sensors using EKF(Extended Kalman Filter). We also describe the information about landmarks detected in the environment. Finally, the robot experiments show the efficiency of our approach in the real environment.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.95.1-95
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• 2002

<1. New level meter inside the fuel tank> Ultrasound level sensors are widely applied as level meters of liquid tank. Measurement instrument of level between water and fuel is developed. Since the fuel is inflammable, the sensor system doesn't allow to include any electric circuit inside the fuel tank. The optical cable sensor can satisfy this explosive condition. The measurement method with ultrasonic sensor is attached on the tank wall or tank manhole lid. The pressure sensor can't be applied inside the gasoline fuel tank. An ultra-sonic sensor doesn't detect a enough signal reflected from water level deep under gasoline fuel. The pressure sensor is difficult to measure the height o...

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1830-1833
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• 2015

모든 사물이 통신으로 연결되는 사물인터넷(IoT) 시대가 도래 하면서, IoT센서를 통한 데이터 시각화에 대한 요구가 증가 하고 있다. 본 연구에서는 전문적인 지식이 없는 사람도 쉽게 방대한 센서 데이터를 저장, 수집 후 쉽게 데이터 시각화할 수 있는 시스템을 구성 하였다. 본 논문에서는 데이터 시각화를 접근성이 용이한 웹 브라우저에서 구현하였고, 웹 브라우저에서 이를 구현하기 위해서는 웹의 다양한 비표준 플러그인(Flash, SilverLight, ActiveX 등)을 사용해야하는 불편함있다. 이를 개선하기 위해 HTML5, CSS, Javascript를 사용해 플러그인을 설치하지 않고 초음파 센서를 사용한 데이터의 실시간 차트 구현을 하였다. 본연구의 결과는 향후, 초음파 센서데이터를 활용한 전후방 장애물 감지 센서, 도난 경보 시스템, IoT센서 데이터 시각화 서비스 등에 활용 될 것으로 기대된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.501-503
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• 2013

This project presents a concept of mobile robots using prototypes, computing proposal oriented to embedded systems implementation. We implement our system using GPS module, Ultrasonic sensor(range sensors), H-bridge dual stepper control, DTMF(Dual-tone Multi-Frequency ) and LCD module. In this paper we construct a mechanical simple mobile robot model, which can measure the distance from obstacle with the aid of sensor and should able to control the speed of motor accordingly. Modules were interfaced with FPGA(Field Programmable Gate Array) controller for hardware implementation.