• Journal of Welding and Joining
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• v.23 no.4
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• pp.53-58
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• 2005

We designed a weld monitoring system with UV and IR sensors using a embedded DSP controller for implementing a distribution system; running stand alone and communication with outside by industrial standard protocols. Also this system provided a USB port in order to be acquiring data in PC. The user interface program in PC visualized the IR and W data in time, frequency and state space. A correlation of IR and UV signals showed closely related to weld quality. A rapid change of geometry can be found through a moving average filter. And the average value of IR signal at an interval represented a welding width and depth. Through these results, we proposed a monitoring algorithm for a integer type DSP.

• Journal of Magnetics
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• v.21 no.4
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• pp.524-528
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• 2016

Eddy current (EC) sensor works based on the electromagnetic induction principle and has been widely applied in the industrial testing and evaluation due to its robustness and environmental adaptability. Meanwhile, tilt angle measurement is mainly based on the laser or visual method, which is strict with the measurement environment and not suitable for the industrial applications. In this paper, a novel tilt angle measurement method based on arrayed EC sensors is proposed. Both the simulation and experiments indicate that the measured error is approximately linear with tilt angle and the accuracy after compensation is $0.25^{\circ}$. In conclusion, this research cannot only broaden the scope of EC application, but also overcome the shortcomings of existing angle measurement methods.

• Journal of Sensor Science and Technology
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• v.32 no.1
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• pp.62-65
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• 2023

The wave mode calculation of a large-scale optical system in comparison to the working wavelength is practically impossible because the computational cost increases exponentially. In this paper, we propose a method that can obtain the optical mode in a large-scale optical system. The method carries out simulations by dividing the calculation area into blocks and moving along the light axis along which the light propagates. By applying this method to the calculation of resonant modes in a ring-type optical resonator, which is mainly used for ring laser optical gyro sensors, the efficiency of the proposed method was verified.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.280-284
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• 2023

In this study, a prototype micro-scale photomask and microfluidic channel mold were fabricated using the thermal shrinkage of the polymer. A polystyrene (PS) sheet was used as the heat-shrink polymer, and the patterns of the photomask and microchannel are interdigitated electrodes. Patterns were formed on the PS sheets using a commercial laser printer. The contraction ratio of the PS sheet was approximately 60% at a temperature of 150 ℃, and the transmittance was reduced by approximately 0% at a wavelength of 365 nm. The microfluidic channel had a round shape. The proposed technique is simple, facile, and inexpensive for fabricating a micro-scale photomask and microfluidic channel mold and does not involve the use of any harmful materials. Thus, this technique is well-suited for fabricating diverse micro-scale patterns and channels for prototype devices, including sensors.

• Journal of Sensor Science and Technology
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• v.22 no.1
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• pp.84-88
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• 2013

In this paper, the low price signal generator with capability of frequency high-resolution and variable sync pulse has implemented. It fulfils well the requirements for SS-OCT of the frequency resolution less than 1Hz, frequency stability of ${\leq}{\pm}0.5Hz$/10 min and variable sync pulse output timing. Through its performance test applied to wavelength swept laser, 120 nm sweeping range and 10 mW average optical power were obtained. This shows that the realized sine-wave generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.

• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.334-337
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• 2015

Pure ZnO, ZnO nanowires doped with 3 wt.% Ga (3GZO) and doped with 3 wt.% Ag (3SZO) were grown by a hot-walled pulse laser deposition (HW-PLD) technique. The optical and chemical properties of Ga and Ag doped nanowires was analyzed. Nanowires were determined to be under 200 nm in diameter and several μm in length. Change of significant resistance was observed and the gas detection sensitivities of ZnO, 3GZO and 3SZO nanawires were compared. The sensitivities of ZnO, 3GZO, and 3SZO nanowire sensors were measured at 300℃ for 1 ppm of ethanol gas at 97%, 48%, and 203%, respectively.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.49-52
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• 2007

Terrestrial Laser Scanning(TLS) was developed at the mid-to-late 1990s. This technique enables to perform reconnaissance surveying of regions or structures hard to access. Besides, TLS has been extended its application gradually such as preservation of historical remains, underground surveys, slopes, glaciers monitoring and so on. However, though the technique has a lot of advantages, an application for structural health and safety monitoring is a beginning stage and it need much research. Therefore in this study, as a groundwork, the estimation model on stress of structures using TLS and Finite Element Method(FEM) applied by the Digital Elevation Model(DEM) technique of geoinformatics is proposed. For the verification of this model, experiments were performed with a continuous steel beam subjected to point loads and outputs were compared with those of electrical strain sensors.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.6
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• pp.614-619
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• 2009

An engine for marine propulsion and power generation consists of several cylinder liner-piston sets. And the oil groove is on the cylinder liner inside wall for the lubrication between a piston and cylinder. The machining process of oil groove has been carried by manual work so far, because of the diversity of the shape. Recently, we developed an automatic grinding robot system for oil groove machining of engine cylinder liners. It can covers various types of oil grooves and adjust its position by itself. The grinding robot system consists of a robot, a machining tool head, sensors and a control system. The robot automatically recognizes the cylinder liner's inside configuration by using a laser displacement sensor and a vision sensor after the cylinder liner is placed on a set-up equipment.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.530-535
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• 2002

An approach for quickly updating GIS building data using high resolution remotely sensed data is proposed in this paper. High resolution remotely sensed data could be aerial photographs, satellite images and airborne laser scanning data. Data from different types of sensors are integrated in building extraction. Based on the extracted buildings and the outdated GIS database, the change-detection-template can be automatically created. Then, GIS building data can be fast updated by semiautomatically processing the change-detection-temp late. It is demonstrated that this approach is quick, effective and applicable.

• Journal of Sensor Science and Technology
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• v.17 no.3
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• pp.157-161
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• 2008

An optical sensor was developed to detect nanoparticles, turbid materials and microorganisms in water simultaneously. Three different light sources like UV-LED, NIR-LED and laser diode have been employed to develop the optical sensor based on the scattering light and fluorescence light. The sensor system has high selectivity and sensitivity, that it can be used to monitor the quality of drinking water.