• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.142-148
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• 2007

A mechanically induced long-period fiber grating array was fabricated and its transmission characteristics were measured. The grating away consisted of a rubber cover and a 45 cm metal bar with 10 grating groups. Each grating group was composed of 60 gratings. The period of the grating of the grating groups was increased by $10{\mu}m$ increments from $690{\mu}m$ to $780{\mu}m$. The long period fiber grating was induced when the pressure was applied on the long period grating array and the resonant wavelength depended on the position of applied pressure. The experimental results shows that this long period fiber grating away can be used as a various band rejection filter or a fiber optic sensor.

• Journal of Sensor Science and Technology
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• v.5 no.3
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• pp.65-73
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• 1996

One of the important factor in drug stuffs to a patient is to inject exact amount with stable flow rates. Since improper injection amount and flow rates would cause bad effect to recovery of a patient, the detecting sensors with high sensitivity is required for an injection pump systems' performance improvement. In this study, the three sensors, piezo film sensor, photo transistor and photo array, were compared to find best one for an injection pump monitoring system. Using suggested data processing technique and photo array sensors, we could minimize the effect of interference, disturbance, illumination, and sensitivity change caused by sensor's position. According to the experiments, the photo array showed the higher reliance than any other the three types of sensors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.50-51
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• 2011

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.62-70
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• 2011

Nowadays image sensor is an essential component in many multimedia devices, and it is covered by a color filter array to filter out specific color components at each pixel. We need a certain algorithm to combine those color components reconstructed a full color image from incomplete color samples output from an image sensor, which is called a demosaicking process. Most existing demosaicking algorithms are developed for ideal image sensors, but they do not work well for the practical cases because of dissimilar characteristics of each sensor. In this paper, we propose a new demosaicking algorithm in which the color filter characteristics are fully utilized to generate a good image. To demonstrate significance of our algorithm, we used a commerically available sensor, CBN385B, which is a sort of Honeycomb-style CFA(Color Filter Array) CCD image sensor. As a performance metric of the algorithm, PSNR(Peak Signal to Noise Ratio) and RGB distribution of the output image are used. We first implemented our algorithm in C-language for simulation on various input images. As a result, we could obtain much enhanced images whose PSNR was improved by 4~8 dB compared to the commonly idealized approaches, and we also could remove the inclined red property which was an unique characteristics of the image sensor(CBN385B).Then we implemented it in hardware to overcome its problem of computational complexity which made it operate slow in software. The hardware was verified on Spartan-3E FPGA(Field Programable Gate Array) to give almost the same performance as software, but in much faster execution time. The total logic gate count is 45K, and it handles 25 image frmaes per second.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.111-120
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• 2016

Education equipment for field programmable gate array (FPGA) design of sensor-based IOT (Internet Of Thing) system is introduced. Because sensors have different interfaces, several types of interface controller on FPGA need. Using this equipment, several types of interface controller, which can control ADC (analog-to-digital converter) for analog sensor outputs and $I^2C$ (Inter-Integrated Circuit), SPI (Serial Peripheral Interface Bus), and GPIO (General-Purpose Input/Output) for digital sensor outputs, can be designed on FPGA. Image processing hardware using image sensors and display controller for real and image-processed images or videos can be design on FPGA chip. This equipment can design a SOC (System On Chip) consisting of a hard process core on Linux OS and a FPGA block for IOT system which can communicate with wire and wireless networks. Using the education equipment, an example of hardware design using image sensor and accelerometer is described, and an example of syllabus for "Digital system design using FPGA" course is introduced. Using the education equipment, students can develop the ability to design some hardware, and to train the ability for the creative capstone design through conceptual, partial-level, and detail designs.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.281-285
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• 2009

Mobile robot has various sensors for describing the external world. The ultrasonic sensor widely applied to the most mobile robot to detect the obstacle and environment owing to low cost, its easy to use. However, ultrasonic sensor has major problems: the uncertainty information of sensor, false readings caused by specular reflection, multi path effect, low angular resolution and sensitivity to changes in temperature and humidity. This paper describes a sensor system for map building of mobile robot. It was made of low cost PSD (Position Sensitive Detector) sensor array and high speed RISC MPU. PSD sensor is cost effective and light weighting but its output signal has many noises. We propose heuristic S/W filter to effectively remove these noises. The developed map building sensor system was equipped on a mobile robot and was compared with ultrasonic sensor through field test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.987-995
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• 2009

As an experimental technique to analyze the far-field characteristics of underwater cylindrical array sensors, cylindrical acoustic holography is studied. Inside an laboratory water tank, far-field directivity patterns as well as near-field source images are reconstructed from the measured hologram by hydrophone array. Approximate equation for far-field directivity estimation is derived based on stationary phase method. The simulation and experiment show well usefulness of the proposed method in application of underwater array sensors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.111-116
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• 2009

As an experimental technique to analyze the far-field characteristics of underwater cylindrical array sensors, cylindrical acoustic holography is studied. Inside an laboratory water tank, far-field directivity patterns as well as near-field source images are reconstructed from the measured hologram by hydrophone array. Approximate equation for far-field directivity estimation is derived based on stationary phase method. The simulation and experiment show well usefulness of the proposed method in application of underwater array sensors.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.19-24
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• 2014

This article reviews the recent progress in nanowell array biosensors that use the label-free detection protocol, and are detected in their natural forms. These nanowell array biosensors are fabricated by nanofabrication technologies that should be useful for developing highly sensitive and selective also reproducible biosensors. Moreover, electrochemical method was selected as analysis method that has high sensitivity compared with other analysis. Finally, highly sensitive nanobiosensor was achieved by combining nanofabrication technologies and classical electrochemical method. Many examples are mentioned about the sensing performance of nanowell array biosensors will be evaluated in terms of sensitivity and detection limit compared with other micro-sized electrode without nanowell array.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.3
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• pp.242-247
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• 2009

The ability of time reversal techniques to focus ultrasonic beams on the source location is important in many aspects of ultrasonic nondestructive evaluation. In this paper, we investigate the time reversal beam focusing of ultrasonic array sensors on a defect in layered media. Numerical modeling is performed using the commercially available software which employs a time domain finite difference method. Two different time reversal approaches are considered - the through transmission and the pulse-echo. Linear array sensors composed of N elements of line sources are used for signal reception/excitation, time reversal, and reemission in time reversal processes associated with the scattering source of a side-drilled hole located in the second layer of two layer structure. The simulation results demonstrate the time reversal focusing even with multiple reflections from the interface of layered structure. We examine the focusing resolution that is related to the propagation distance, the size of array sensor and the wavelength.