• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.127-134
• /
• 2015

VLC(Visible Light Communication) is the technology to send and receive data by using visible light that LED emits. The basic principle of VLC is the communication by using flashing(ON/OFF) of the light from the LED that changes electricity to light in short time. As the recent advances in LED technology, VLC is also received a lot of attention and the research about it is in progress actively. Especially, the interest about indoor VLC system is increasing because the visible light can't pass through the wall. In this paper, we compose the indoor SISO VLC system with NRZ-OOK and VPPM modulation schemes. Also, we apply SR-ARQ, a kind of re-transmission error control schemes, to the VLC system. And then, we compare and analyze the performance of communication according to the location of receiver and the type of modulation by using BER, the number of transmission and throughput.

• Current Optics and Photonics
• /
• v.6 no.3
• /
• pp.332-336
• /
• 2022

Given a cubic space, it is easy to uniformly illuminate the floor with light sources placed on top. However, little has been reported about uniform illumination on walls with the same configuration of light sources. Here we present a luminaire consisting of nine light-emitting diodes (LEDs) with perfect Lambertian distribution, placed on the top as a 3 × 3 rectangular LED array. The distances between LEDs and tilt angles of each individual LED are adjustable and optimized by an annealing algorithm. After optimization, the array produces a rectangular illumination pattern on one wall with a uniformity of about 89%. Analysis shows that the tilt angles of individual LEDs are key parameters for uniform side illumination. In a scenario that is more practical, the tilt angles of all the LEDs are set to be the same, only decreasing the uniformity to 83%.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.8
• /
• pp.706-712
• /
• 2013

In this paper, channel modeling of VLC(Visible Light Communication) was investigated under indirect lightning circumstance which was the way that all phontons started from LED(Light Emitting Diode) were reached on the floor with NLOS paths. I supposed width(6m), depth(4m), height(2.2m) cube room circumstance for VLC communication channel and supposed that 4 LEDs were located at 2m height, which emitted photons at the direction of wall and ceiling. Channel characteristics, which were power attenuation and delayed receiving of light signal, were abstracted from receivers(PDs) which were located at 0.5m above from floor. The availability of channel was verified via BPSK based communication simulation.

• Journal of Korean Association for Spatial Structures
• /
• v.11 no.4
• /
• pp.71-78
• /
• 2011

Interactive media are applied to inner and outer space of small public space to enhance for the interaction between the spectator and works, also widely used in the exterior wall by LED and projector for advertisement. In the other hand, case studies of interactive media for large space have not less accomplished than those of buildings and public spaces. Thus, these studies analyzed 11 large structure examples by display, content, interface, and technology device by comparison of those cases of ordinary building public space. First interactive media for large space are found to be contents(39%), and next one is play(27%), advertisement(17%) and message(17%).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.86-87
• /
• 2009

High quality $CuInSe_2$ (CIS) were grown on GaAs substrate by using the hot wall epitaxy method. The behavior of point defects in the CIS layer investigated by using photoluminescence (PL) at 10 K. Point defects originating from $V_{Cu}$, $V_{Se}$, $Cu_{int}$, and $Se_{int}$ were classified as donor or acceptor types. These PL results also led us to confirm that the p-type CIS layer had obviously converted into n-type after the Cu atmosphere treatment. Finally, we found that the In in the CIS layer did not form the native defects, because In existed in the form of stable bonds in the CIS layer.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.4
• /
• pp.354-359
• /
• 1994

An isolate, 90-GT-302, was found to produce antibiotics inducing typical mycelial swelling in Magnaporthe grisea and Fusarium solani. This isolate formed yellow substrate and white rectiflexbiles aerial mycelia in the early stages of growth. The aerial mycelium gradually changed its color to white and finally formed a gray spore mass. Analysis of the cell wall acid hydrolysate revealed the presence of LL- and meso-diaminopimelic acids, glycine, and galactose, which indicated cell wall type X. This result placed our isolate in genus Kitasatosporia. A comparison of isolate 9O-GT-302 with reference strains of Kitasatosporia spp., which not only demonstrated several differences in their physiological properties but also novelty of the active compounds produced by this isolate, led us to designate the isolate as Kitasatosporia kimorexae.

• Journal of Mechanical Science and Technology
• /
• v.15 no.9
• /
• pp.1319-1327
• /
• 2001

The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed 1:1 scale. The model experiments were executed at a lower pressure than that in a real gas turbine. Combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure and NOx emission were measured at partial and full loads for both model and on-site testing. The comparison of these items in the stand and field test results led to has the development of a method of calculation and the improvement of gas turbine combustors.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.05a
• /
• pp.136-137
• /
• 2015

Tilt-up construction is the method that the wall structures are fabricated horizontally on site and placed at specified location using heavy lifting equipment. Tilt-up method generally has several advantages, such as of productivity improvement, labor savings, shortened the construction period the and cost savings. In this study, Tilt-up method is used for wall construction of detached house. Result shores the substantial improvement on construction period. The use of Tilt-up method led construction period reduction of 20%.

• Korean Journal of Agricultural Science
• /
• v.46 no.2
• /
• pp.335-340
• /
• 2019

Two species of Leycesteria, L. gracilis (Kurz) Airy Shaw and L. formosa Wall. (Caprifoliaceae), from the Lao Cai and Yen Bai Provinces are reported here as a new generic record for the flora of Vietnam. During floristic surveys of northern Vietnam, L. gracilis and L. Formosa were encountered. A critical morphological study of all the collected specimens and the type of materials consulting the relevant literature led us to confirm the identity of our collected specimens as L. gracilis and L. formosa. The genus differs from other Vietnamese genera of Caprifoliaceae by the presence of a spike inflorescence or flowers in sessile whorls of 6. Taxonomic notes, description, and photographs are provided, together with short notes on the distribution, ecology and phenology of the two species.

• Journal of Medicine and Life Science
• /
• v.18 no.3
• /
• pp.56-60
• /
• 2021

In recent decades, tissue engineering advances have led to more skin substitutes becoming available. Acellular dermal matrix, initially developed for use in the treatment of full-thickness burns, is made by removing the cellular components from the dermis collected from donated bodies or animals. This class of scaffold is used to replace skin and soft tissue deficiencies in a variety of fields, including breast reconstruction, abdominal wall reconstruction, and burn treatment. Herein, we provide a detailed review of the clinical applications of acellular dermal matrix.