• Journal of IKEEE
• /
• v.26 no.3
• /
• pp.416-421
• /
• 2022

In this study, we present a fully automated system that combines camera technology with liquid crystal technology to create a polarization camera capable of detecting the partial linear polarization of light reflected from an object. The use of twisted nematic (TN) liquid crystals that electro-optically modulate the polarization plane of light eliminates the need to mechanically rotate the polarizing filter in front of the camera lens. Images obtained using these techniques are imaged by computer software. In addition, liquid crystal panels have been produced in a square shape, but many camera lenses are usually round, and lighting or other driving units are installed around the lens, so space is optimized through the application of a circular liquid crystal display. Through the development of this technology, an electrically switchable and space-optimized liquid crystal polarizer is developed.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.53.4-54
• /
• 2021

Although the era of very large telescopes has come, small telescopes still have advantages for fast follow-up and long-term monitoring observation. Intensive monitoring survey of nearby galaxies (IMSNG) aims to understand the nature of the supernovae (SNe) by catching the early light curve from them with the network of small telescopes from 0.4-m to 1.0-m all around the world. To achieve the scientific goals with heterogeneous facilities, three factors are important. First, automatic processes as soon as data is uploaded will increase efficiency and shorten the time. Second, searching for transients is necessary to deal with newly emerged transients for fast follow-up observation. Finally, the Integrated process for different telescopes gives a homogeneous output, which will eventually make connections with the database easy. Here, we introduce the integrated pipeline, 'gppy' based on Python, for more than 10 facilities having various configurations and its performance. Processes consist of image pre-process, photometry, image align, image combine, photometry, and transient search. In the connected database, homogeneous output is summarized and analyzed additionally to filter transient candidates with light curves. This talk will suggest the future work to improve the performance and usability on the other projects, gravitational wave electromagnetic wave counterpart in Korea Observatory (GECKO), and small telescope network of Korea (SOMANGNET).

• Journal of the Korean Institute of Landscape Architecture
• /
• v.46 no.2
• /
• pp.62-68
• /
• 2018

This study investigated the effect of light intensity on the removal of particulate matter by Dieffenbachia amoena 'Marianne' and Spathiphyllum spp.. An acrylic chamber ($600{\times}800{\times}1200mm$, $L{\times}W{\times}H$) modeled as an indoor space and a green bio-filter ($495{\times}495{\times}1000mm$, $L{\times}W{\times}H$) as an air purification device were made of acrylic. The removal of particulate matter PM10 and PM1, the photosynthetic rate, stomatal conductance, and number of stomata of Dieffenbachia amoena 'Marianne' and Spathiphyllum spp. were measured according to three different levels of light intensity (0, 30 and $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$). Regarding the length of time taken for PM10 to reach $1{\mu}g$, the Dieffenbachia amoena 'Marianne' showed a significant difference according to the presence or absence of light, and there was no significant difference shown between light intensity of 30 and $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. As for the Spathiphyllum spp., there was no significant difference between 0 and $30{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$, while a significant difference was shown at $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. After 90 minutes, the PM1, PM10, and $CO_2$ residuals of the Spathiphyllum spp. were lowest at $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. The remaining amount of PM1 and PM10 was lower with the Spathiphyllum spp. than with the Dieffenbachia amoena 'Marianne', even at $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. With both plants, the higher the light intensity, the higher the photosynthetic rate, while the stomatal conductance did not show any significant difference. Spathiphyllum spp. showed a higher photosynthetic rate and stomatal conductance and a greater number of stomata than Dieffenbachia amoena 'Marianne', and stomata were observed in both the front and back sides of the leaves. The air purification effect of Spathiphyllum spp. is considered to be better than Dieffenbachia amoena 'Marianne' at the same light intensity due to such plant characteristics. Therefore, in order to select effective indoor plants for the removal of particulate contamination in an indoor space, the characteristics of plants such as the photosynthetic rate and the number and arrangement of stomata according to indoor light intensity should be considered.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.3
• /
• pp.146-152
• /
• 2013

In this paper, we have proposed and experimentally demonstrated an intensity-based self-referencing fiber optic sensor. The proposed fiber optic sensor consists of a broadband light source (BLS), fiber Bragg grating (FBG), tunable Fabry-Perot (F-P) filter, and LabVIEW program. We define the measurement parameter (X) and the calibration parameter (${\beta}$) to determine the transfer function(H) of the self-referencing fiber optic sensor, and the validity of the theoretical analysis is confirmed by experiments. The self-referencing characteristic for the proposed system has been validated by showing that the measurement parameter (X) is invariant for BLS optical power attenuations of 0 dB, 3 dB, and 6 dB. Also, the measured result is irrelevant to the FBGs with different characteristics. This means that the proposed fiber optic sensor offers the flexibility for determining the FBGs needed for implementation. Experimental results for the proposed fiber optic sensor are in good agreement with a theoretical analysis for BLS optical power attenuations and for three FBG pairs with different characteristics. So, the proposed fiber optic sensor has several benefits, including the self-referencing characteristic and the flexibility to determine the FBGs.

• Journal of IKEEE
• /
• v.24 no.2
• /
• pp.638-648
• /
• 2020

Currently, the method of user-follwoing in intelligent cooperative robots usually based in vision system and using Lidar is common and have excellent performance. But in the closed space of Corona 19, which spread worldwide in 2020, robots for cooperation with medical staff were insignificant. This is because Medical staff are all wearing protective clothing to prevent virus infection, which is not easy to apply with existing research techniques. Therefore, in order to solve these problems in this paper, the ultrasonic sensor is separated from the transmitting and receiving parts, and based on this, this paper propose that estimating the user's position and can actively follow and cooperate with people. However, the ultrasonic sensors were partially applied by improving the Median filter in order to reduce the error caused by the short circuit in communication between hard reflection and the number of light reflections, and the operation technology was improved by applying the curvature trajectory for smooth operation in a small area. Median filter reduced the error of degree and distance by 70%, vehicle running stability was verified through the training course such as 'S' and '8' in the result.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.9
• /
• pp.1248-1256
• /
• 1993

The propagation and delay properties in opical fiber are particularly attractive because digital signal processing and conventional analog signal processing techniques such as those using surface acoustic wave devices are limited In their usefulness for signal bandwidth exceeding one or two GHz, although they are very effective at lower frequencies. Since an accurate, low loss and short time delay elements can be obtained by using such an optical fiber, optical signal precessing has attracted much attention for high speed and broad-band signal precessing in particular channel separation filtering for optical FDM signals. In this paper, we consider a coherent optical lattice filter, which uses coherent light sources and consists of directional couplers and optical fiber delay elemnts. The optical fiber fitters are more restricted than the usual digital filters. The reasons are as follows. 1) the coupling coefficients of directional couplers are restricted to the number between 0 and 1. 2) optical signal E(complex amplitude) is divided into J If-$\boxUl$ and J L/7$\div$$\boxUl$ at the directional coupler. Considering these restrictions and in this case all the coupling coefficients of summing and branching elements are set to be equal, we have given design formulae for optical lattice filter, which make the best use of optical signal energy.

• Korean Journal of Optics and Photonics
• /
• v.18 no.6
• /
• pp.383-388
• /
• 2007

A color filter was demonstrated incorporating a patterned metal grating in a quartz substrate. The filter is created in a metal layer perforated with a symmetric two-dimensional array of circular holes, with the pitch smaller than the wavelength of the visible light. A finite-difference time-domain simulation was performed to analyze the device by investigating the effect of structural parameters like the grating height, the period, the hole size, and the refractive index of the hole-filling material on its performance. The device performance was especially optimized by controlling the refractive index of the material comprising the holes of the grating. And two different devices were fabricated by means of the e-beam direct writing with the following design parameters: the grating height of 50 nm, the two pitches of 340 nm for the red color and 260 nm for the green color. For the prepared device with the period of 340 nm, the center wavelength was 680 nm and the peak transmission 57%. And for the other device with the pitch of 260 nm, the center wavelength was 550 nm and the peak transmission was 50%. The filling of the hole with a material whose refractive index is matched to that of the substrate has led to an increase of ${\sim}15%$ in the transmission efficiency.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.530-533
• /
• 2002

We present a case of The Miller Fisher Syndrome (MFS), showing a remission during a recently developed noninvasive therapy. Two weeks after an appearance of cough and fever, a 35 years old Japanese male developed diplopia, ataxia and numbness of his fingers and toes. He was diagnosed as MFS, and a fixed dose of prednisolone acetate (60mg/day) was administered for 3 months, but little improvement was observed. In addition to this administration, we tried 20 minutes of Photic Feedback (PFB) treatment daily for 40 days. The PFB system detects brain waves from the subject's forehead, and extracts alpha waves by the band-pass filter with a center frequency set at 10.0Hz. It also simultaneously modulates the augmentation of a red light-emitting diode, corresponding with the amplitudes of the extracted alpha waves. In this treatment, this adjusted photic stimulation was given to the subject's closed eyes, resulting in the effective alpha enhancement by photic driving response. The numbness increased during each of PFB treatment, but the symptoms started to improve gradually after 10 days. Other symptoms disappeared after 40 days. CD20 levels increased with this treatment. This case suggests that the PFB treatment may speed the natural remission of MFS. This treatment may be worth considering in patients who suffer polyneuropathy.

• Clinical and Experimental Reproductive Medicine
• /
• v.19 no.1
• /
• pp.1-8
• /
• 1992

A fluorescence microscopy technique using flurescein diacetateCFDA) as a substract has been tested for the evaluation of the viability of early mouse embryos. Embryos were incubated in T6 containing FDA concentrations of 2.5 to $50{\mu}g/ml$ for 1 to 5min. Embryos were then examined by reflected light fluorescence using a KP 490 and 520 barrier filter in a Nicon Diaphot microscopy. The results were as follow. 1. The rate of fluorescein accumulation increased on the concentration on FDA from $2.5{\times}10^{-6}M$ to $20{\times}10^{-6}M$ 2. The rate at which intracellular fluorescein was lost from embryos was depended on the temperature at which are stored. 3. Embryos with 3 min exposure to FDA have the most intensity of fluorescence. 4. Exposure of 2 cell embryos to FDA ($2.5-5{\mu}g/ml$) for 1 min did not alter their ability to delope normally in vitro.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.8C
• /
• pp.1184-1192
• /
• 2004

A real-time pupil detection system that detects the pupil movement from the real-time video data achieved by the visual light camera for general purpose personal computer is proposed. It is implemented with three steps; at first, face region is detected using the Haar-like feature detection scheme, and then eye region is detected within the face region using the template-based scheme. Finally, pupil movement is detected within the eye region by convolution of the horizontal and vertical histogram profiling and Gaussian filter. As results, we obtained more than 90% of the detection rate from 2375 simulation images and the data processing time is about 160㎳, that detects 7 times per second.