• International Journal of Advanced Culture Technology
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• 제5권2호
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• pp.54-62
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• 2017

Currently, falling to industrial field workers is causing serious injuries. Therefore, many researchers are actively studying the fall by using acceleration sensor, gyro sensor, pressure sensor and image information.Also, as the spread of smartphones becomes common, techniques for determining the fall by using an acceleration sensor built in a smartphone are being studied. The proposed method has complexity due to fusion of various sensor data and it is still insufficient to develop practical application. Therefore, in this paper, we use acceleration sensor module built in smartphone to collect acceleration data, propose a simple falling algorithm based on accelerometer sensor data after normalization and preprocessing, and implement an Android based app.

• 한국정밀공학회지
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• 제22권8호
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• pp.50-56
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• 2005

This paper is described a development of an optical fiber displacement sensor. The optical fiber sensor using an intensity modulated measures the displacement between target and sensor. A prototype sensor is composed of a transmitting part, a receiving part and a signal processing circuit. The experiment was conducted not only the sensor performance but also factors that affect intensity. The main performance of this sensor is resolution of 0.37um and the non-linearity $0.7\%$ FS and the dynamic bandwidth of about 6.3kHz. As a result of rotation test, the prototype sensor showed an equivalent performance to a commercial eddy current sensor.

• 한국정밀공학회지
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• 제24권10호
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• pp.83-90
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• 2007

The vehicle dynamic control system needs to detect the yaw rate of vehicle and a yaw rate sensor is required as a central component. Therefore, A sensor on the basic of the "tuning fork method" for automotive controls is being developed. The sensor was fabricated by the surface micro machining process to miniaturize its size. The sensor output offset is ${\pm}0.37^{\circ}/sec$ in the room temperature. The resonance frequency of the fabricated yaw rate sensor is measured to 5.29kHz for the drive mode. Tests of the sensor demonstrate that its performance is equivalent to that required for implementation of a yaw control system. Vehicle handling and safety are substantially improved using the sensor to implement yaw control.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.747-752
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• 2008

Fiber-guided sensor system using a generator and a receiver can detect the amplitude of load or pressure. However, this type of sensor can show some difficulties in detecting the location of damages and pressure loadings. To overcome this weakness of this type, the ultrasonic active fiber sensor, which has an integrated ultrasonic generator and sensing part, was developed in this study. By using this sensor system, the location of mechanical loads can be exactly detected. Moreover, the ultrasonic active fiber sensor is more cost-effective than an ultrasonic fiber sensor using two piezoelectric transducers which are used as a generator and a receiver, respectively. Two applications of the ultrasonic active fiber sensor are demonstrated: cure monitoring of lead and measurement of liquid level. Present results showed that the active fiber sensor can be applied for various environmental sensing.

• 센서학회지
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• 제6권2호
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• pp.131-136
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• 1997

The ISFET(ion sensitive field effect transistor), a semiconductor ion sensor, has many advantages over conventional ion sensors. Various single-sensor type ISFET pH-meters have been developed. However, they could not be applied in fields because their performances are directly affected by the sensor condition. With only one sensor, the system could be easily damaged from environmental factors, and reliability of it is decreased. Therefore, a 4-channel PH-meter system is proposed to improve the reliability of ISFET pH-meter. It has 4 ISFETS as ion sensor, and a software which contains a new calibration and measurement algorithm appropriate to the system. The reliability of the system was proved by measuring hydrogen ion concentration in the pH standard solutions and buffer solutions.

• 센서학회지
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• 제16권3호
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• pp.192-196
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• 2007

A fiber-optic interferometric temperature sensor is fabricated using a hollow optical fiber with 8 um air hole. This interferometric sensor for measuring temperature consists of 13 mm long hollow optical fiber whose one end is attached to the single mode fiber and the other end is cleaved. After the sensor is put in a furnace, the phase change of the sensor output signal is measured as the temperature of the furnace increases from $28^{\circ}C$ to $100^{\circ}C$. The phase change of the fiber sensor is proportional to the change of temperature and the relationship between the change of phase and temperature is approximately linear. The sensitivity of this sensor is $2.7{\;}radians/^{\circ}C$.

• 정보학연구
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• 제12권3호
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• pp.1-6
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• 2009

This paper has focused on the development of an educational sensor network (ESN) based on wireless sensor networks(WSN) and pervasive monitoring systems for students' activity during scientific experiments. A number of WSN systems have been proposed with integrated wireless transmission, mounted sensor boards and local processing. However, there is no trail to employ WSN on the educational field. In this paper, to facilitate research and development using wireless sensor network and multi-sensor data fusion, the educational sensor network (ESN) hardware development platform is presented. The ESN project is conducted over one semester time period (Spring Semesters). It involves approximately twenty middle school students who enrolled a gifted program in Kongju National University. Though under prepared, these students are in general highly motivated to learning specially when presented with the ESN project. An ESN project such as this is expected to provide an excellent means for teaching and learning scientific and mathematical principles.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.214-214
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• 2000

This paper deals with the non contact optical sensor to measure the shape of transparent plates such as glass panel of LCD(Liquid Crystal Display). The conventional methods to obtain the shape or thickness of a transparent plates are contact type sensor such as LVOT(Linear Variable Differential Transformer). Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition, the high temperature glass casting makes the size of sensor body changed. These reasons makes the sensor degraded. In this paper, to overcome these problem, we proposed a low cost noncontact optical sensor this is composed of the Hologram laser unit of a CD-Pickup and a plastic lens. To evaluate the performance of the proposed optical sensor, a series of experiments were performed for various measurement condition. Based upon observation of the experimental result, the developed sensor shows good result for measuring the shape of transparent plates.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.291-295
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• 1996

This paper discusses several design factors of a capacitance displacement sensor with a numerical method and several experiments and describes guide lines of the design of this type sensor. We introduce the charge density method for the analysis of this type sensor, which has feasible accuracy and efficiency. The analysis of this type sensor with the charge density method agrees with displacement sensitivity experiments of a circular plate capacitance sensor with the sensor amp based In the charge transfer principle.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3357-3376
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• 2015

Wireless sensor network is an important research topic that has attracted a lot of attention in recent years. However, most of the interest has focused on wireless sensor network to gather scalar data such as temperature, humidity and vibration. Scalar data are insufficient for diverse applications such as video surveillance, target recognition and traffic monitoring. However, if we use camera sensors in wireless sensor network to collect video data which are vast in information, they can provide important visual information. Video sensor networks continue to gain interest due to their ability to collect video information for a wide range of applications in the past few years. However, how to efficiently store the massive data that reflect environmental state of different times in video sensor network and how to quickly search interested information from them are challenging issues in current research, especially when the sensor network environment is complicated. Therefore, in this paper, we propose a fast algorithm for extracting key frames from video and describe the design and implementation of key frame extraction and sharing in Android for wireless video sensor network.