• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.10B
• /
• pp.1252-1257
• /
• 2011

In this paper, efficient functions for audio spectrum mapping with visible spectrum are proposed. Through mapping overall hearing frequency band with visible frequency band, emotional lighting might be possible. We propose a basic linear mapping function and non-linear mapping functions emphasizing specific audio frequency bands. For the algorithm implementation, spectrum analysis method and filter method are introduced. Especially, in this paper, a prototype LED lighting equipment using the digital filter method is implemented. The proposed lighting method can be applied to many LED lighting area using music.

• Journal of Korean society of Dental Hygiene
• /
• v.8 no.3
• /
• pp.115-126
• /
• 2008

Purpose : The research which sees width for a wide gain and loss is about brush qualitative management of the child about dental hygiene of the child is investigated the brush qualitative actual condition. Methods : The data which is collected used SPSS(Statistical Package for the Social Science) WIN 11.5 programs and analyzed, a frequency and a percentage with analytical technique, in order to grasp the general quality of the investigation object person produced to examine is about the brush quality control actual condition of the children opinion t-test (verification) frequency analyses and $x^2$(Chi-square) verifications, executed. Result : The followings are the findings of this research. First, the children about the reason which wipes this 83.4% the thing protection dental caries answer back, followed in grade and considers the difference which was visible(p<0.001). Second, wipes whether to experience is educated answer back 83.0% was educated, followed in sex and considers the difference which was visible(p<0.05). Third, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.01). Fourth, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.01). Fifth, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.05, p<.001). Sixth, Use duration of the toothbrush the child of most was 3~6 months, according to grade and sex was visible the difference which considers. Conclusion : Are oral healthily of the children is the knowledge which relates with a brush quality and practical degree important. Therefore this there must be dental health education program development will be able to improve, means must reflect the dental health education at the time of.

• Journal of the Korean Applied Science and Technology
• /
• v.24 no.1
• /
• pp.1-9
• /
• 2007

It prepared the $TiO_2$ powder which has photo-catalytic activity in the visible-light by the wet process with titanium oxysulfate. The titanium $dioxide(TiO_2)$ by the wet process creates a new absorption band in the visible light region, and is expected to create photocatalytic activity in this region. Anatase $TiO_2$ powder which has photocatalytic activity in the visible light region, is treated using microwave and radio-frequency(RF) plasma. But, the $TiO_2$ powder for the visible light region, which also can be easily produced by wet process. The wet process $TiO_2$ absorbed visible light between 400nm and 600nm, and showed a high activity in this region, as measured by the oxidation removal of aceton from the gas phase. The AH-380 sample appears the yellow color to be strong, the catalytic activity in the visible ray was excellent in comparison with the plasma-treated $TiO_2$. The AH-380 $TiO_2$ powder, which can be easily produced on a large scale, is expected to have higher efficiency in utilizing solar energy than the plasma-treated $TiO_2$ powder.

• Journal of Satellite, Information and Communications
• /
• v.8 no.2
• /
• pp.44-49
• /
• 2013

LED communication is a wireless communication technology to transmit information using visible light coming out from the LED(Light Emitting Diode). It is a technique that can overcome RF(Radio Frequency) communication problems that are frequency allocations, human body hazards, security vulnerabilities, and interference between electronic devices. As a technique that can be used as lighting and communications with using LED, LED communication is suitable for ubiquitous environment. This paper introduces the process of data transmission algorithm for LED communication systems algorithm using LED, PD(Photodiode), and MCU(Micro Controller Unit).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.469-471
• /
• 2021

As wireless communication technology advances to ensure high accuracy and safety at high speeds, research and development of Visible Light Communication (VLC) technology has been accelerated as an alternative to traditional radio frequency (RF) technology. As the radio spectrum of RF communication becomes more congested and demand for bandwidth continues to increase, VLCs that can use unlicensed frequency band are proposed as a solution. However, VLC channels have broadcasting characteristics that make them easily exposed to eavesdropping and jamming attacks, and are vulnerable to MITM (Man-In-The-Middle) due to their line of sight (LOS) propagation characteristics. These attacks on VLC channels compromise the confidentiality, integrity, and availability of communications links and data, resulting in higher data retransmission rates, reducing throughput and increasing power consumption, resulting in lower data transmission efficiency. In this work, we model vulnerable VLC channels to analyze the impact of attacks and communications vulnerabilities by malicious jammers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.641-642
• /
• 2018

LED-based visible light communication requires separate transmission and reception equipment and is capable of communication only in the range of the light source. Also, there is an advantage that it can be used in a frequency sensitive area using a visible light band. Research is needed to apply these advantages and characteristics to various fields. In this paper, we implemented and verified the functions of the visible light communication system using broadcast methods.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.9
• /
• pp.787-796
• /
• 2013

In this paper, the visible light communication (VLC) techniques based on the carrier modulation are considered in order to realize the VLC application service that has the functions of the high speed optical sensing and the wide range reception from VLC transmitter. The VLC hardware circuits based on the 32.768 kHz low frequency carrier and 4 MHz high frequency carrier are designed and implemented respectively, and the signal waveform generated from the implemented circuits are observed. In addition, various performance experiments are done with the prototypes.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.11
• /
• pp.2043-2047
• /
• 2010

This study is to solve problems of depletion of RF bandwidth frequency, confusion possibility, security that current wireless communications system have and is to confirm possibility of applying next generation network. To solve problems of current wireless communications system, visible light communications system for power line communications using ATmega16 Microcontroller is was realized and receiver property was analyzed. PLC exclusive chip APLC-485MA, Microcontroller ATmega16, 5pi bulb type LED and high flux LED, visible light receiving sensor LLS08-A1 were used for transmitter and receiver. Performance was analyzed by designed program and an oscilloscope. It was showed average 20% improved receiver rate rather than bulb type LED in the case of high flux LED through voltage change rate on communication distance and LED type of distance between 10 to 50 cm. The blue LED showed the best performance among measured LED types with above 10% of voltage decreasing rate. But As it gradually becomes more distant, the precise date was difficult to obtain due to weak light. To overcome these sort of problems, specific values such as changing conditions and efficiency value relevant to light emitting parts and visible light receiving sensor should be calculated and continuous study and improvements should also be accomplished for the better communications condition.

• The Korean Journal of Zoology
• /
• v.19 no.1
• /
• pp.15-24
• /
• 1976

The frequency of the second chromosomes bearing deleterious genes in the Anyang natural population of Korea in Drosophila melanogaster was repeatedly estimated during the period from 1971 through 1973. 1) The frequency of lethal and semilethal chromosomes was calculated to be 28.2%, and the frequencies were maintained without fluctuation for three years. 2) Allelism rate between lethal genes isolanted from each year was 0.77% on the average. The rate of elimination of lethal genes $(IQ^2)$ was estimated to be 0.0008. 3) The frequency of sterile gene on the second chromosomes was estimated to be 9.1% for females, 6.8% for males and 2.0% for both sexes, respectively. 4) Recessive visible mutant genes, namely rbl and bw genes, were frequently extracted when the chromosomes were revealed in homozygous. The frequencies of these mutants were found to be 1.3% for bw genes and 2.7% for rbl genes, respectively.

• ETRI Journal
• /
• v.37 no.4
• /
• pp.677-684
• /
• 2015

Recently, orthogonal frequency-division multiplexing (OFDM) was applied to VLC systems owing to its high rate capability. On the other hand, a real-valued unipolar OFDM signal for VLC significantly reduces bandwidth efficiency. For practical implementation, channel estimation is required for data demodulation, which causes a further decrease in spectral efficiency. In addition, the large fluctuation of an OFDM signal results in poor illumination quality, such as chromaticity changes. This paper proposes a spectrally efficient method based on a hidden-pilot-aided precoding technology for VLC with less flickering than a conventional OFDM-based method. This approach can obtain channel information without any loss of bandwidth efficiency while ensuring illumination quality by reducing the flickering effect of an OFDM-based VLC. The simulation results show that the proposed method provides a 6.4% gain in bandwidth efficiency with a 4% reduction in flicker compared to a conventional OFDM-based method.