• Title/Summary/Keyword: $\b{LED}$

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A Basic Study on the R. G. B LEDs for the Natural Color Realization (R,G,B LEDs의 Natural Color 조명색채 구현 방안에 대한 기초연구)

  • Jung, Yeon-Hong;Park, Byoung-Chul;Kim, Hyun-Sun;Choi, An-Seop
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2009.10a
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    • pp.3-6
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    • 2009
  • This research is an experiment to examine on the realization of Natural Color using R, G, B LEDs and this experiment was performed to cover two different stages. 1) When Natural Color using R, G, B LEDs was realized without correction in first stage, all color(R, G, B, C, M, Y) series had highly range of error from 0.0200 to 0.1500. 2) When R, G, B of LEDs was mixed at the ratio of 1:4.5907:0.0601 for realization of white in second stage, white was not realized to excitation purity. The second stage was Performed based on the three primary colors theory found out by Thomas Young in England and Hermann Ludwig Ferdinand von Helmholtz in Germany.

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The management and treatment of chronic hepatitis B in Korean children (소아 만성 B형 간염의 관리와 치료)

  • Choe, Byung-Ho
    • Clinical and Experimental Pediatrics
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    • v.50 no.9
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    • pp.823-834
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    • 2007
  • Interferon (IFN) alpha has been the first line therapy of chronic hepatitis B in children, but HBeAg seroconversion occurred in 26% of treated children compared to 11% of controls in multinational randomized controlled study. Recently, lamivudine was shown to be a potent inhibitor of Hepatitis B virus (HBV) reproduction both in HBeAg positive and in HBeAg negative (the pre-core mutant form) chronic hepatitis in randomized studies worldwide. Lamivudine therapy led to considerable improvement in the seroconversion rate of HBeAg in children with chronic hepatitis B, though long-term therapy resulted in the expansion of lamivudine-resistant mutant viruses. Combination therapy with lamivudine plus alpha-IFN does not seem to improve HBe Ag seroconversion. Above all, the most effective way to prevent hepatitis B is universal HBV vaccination.

Modeling slump of concrete with fly ash and superplasticizer

  • Yeh, I-Cheng
    • Computers and Concrete
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    • v.5 no.6
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    • pp.559-572
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    • 2008
  • The effects of fly ash and superplasticizer (SP) on workability of concrete are quite difficult to predict because they are dependent on other concrete ingredients. Because of high complexity of the relations between workability and concrete compositions, conventional regression analysis could be not sufficient to build an accurate model. In this study, a workability model has been built using artificial neural networks (ANN). In this model, the workability is a function of the content of all concrete ingredients, including cement, fly ash, blast furnace slag, water, superplasticizer, coarse aggregate, and fine aggregate. The effects of water/binder ratio (w/b), fly ash-binder ratio (fa/b), superplasticizer-binder ratio (SP/b), and water content on slump were explored by the trained ANN. This study led to the following conclusions: (1) ANN can build a more accurate workability model than polynomial regression. (2) Although the water content and SP/b were kept constant, a change in w/b and fa/b had a distinct effect on the workability properties. (3) An increasing content of fly ash decreased the workability, while raised the slump upper limit that can be obtained.

Multistage Fuzzy Production Systems Modeling and Approximate Reasoning Based on Fuzzy Petri Nets (다단계 퍼지추론 시스템의 퍼지 페트리네트 모델링과 근사추론)

  • 전명근
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.12
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    • pp.84-94
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    • 1996
  • In this work, a fuzzy petri net model for modeling a general form of fuzzy production system which consists of chaining fuzzy production rules and so requires multistage reasoning process is presented. For the obtained fuzzy petri net model, the net will be transformed into some matrices, and also be systematically led to an algebraic form of a state equation. Since it is fond that the approximate reasoning process in fuzzy systems corresponds to the dynamic behavior of the fuzzy petri net, it is further shown that the multistage reasoning process can be carried out by executing the state equation.

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Terpenoid constituents from the aerial parts of Asplenium scolopendrium

  • Sohn, You-Min;Chin, Young-Won;Yang, Min-Hye;Kim, Jin-Woong
    • Natural Product Sciences
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    • v.14 no.4
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    • pp.265-268
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    • 2008
  • Phytochemical investigations on the aerial parts of Asplenium scolopendrium led to the isolation of four terpenoids, the structures of which were assigned as lutein (1), (6S,9S)-roseoside (2), icariside $B_2$ (3), and picrionoside A (4) using spectroscopic data.

Vitamin B-6 Nutritional Status of Breast-fed and Formula-fed Preterm Infants (모체의 비타민 B-6 섭취상태가 조산아의 비타민 B-6 영양상태에 미치는 영향)

  • 강순아
    • Journal of Nutrition and Health
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    • v.28 no.4
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    • pp.321-330
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    • 1995
  • Concentrations of total vitamin B-6 in human milk as well as individual, B-6 vitamers have important implications for the nutritional management of breast-fed(BF) infants. Vitamin B-6 status was assessed in 3 groups of infants : two groups preterm (PT) BF infants whose mothers were supplemented with 2 or 27mg pyridoxine(PN)-HCI ; a sub group of formula-fed (FF) PT infants. Mothers and infants were assessed weekly during the 28-day post feeding. Throughout the neonatal period, levels of total vitamin B-6 and percentages of pyridoxal(PL) in breast milk were lower in PT than T mothers, even in mothers supplemented with 27mg PN-HCI. Total vitamin B-6 levels in PT milk paralleled maternal supplementation but percentage distributions of B-6 vitamers did not change. Vitamin B-6 intakes of BF preterm infants paralleled their mothers' level of infants in the 2mg group was suggested by vitamin status parameters. Vitamin B-6 inadequacy of infants correlated with their plasma pyridoxal-5-phosphate(PLP) levels and erythrocyte alanine aminotransferase(E-ALAT) activity; all parameters such as plasma PLP, PL/PLP ratio and stimulation % of E-ALAT were highest for FF PT infants. The positive correlation of vitamin B-6 levels in breast milk gestational age may contraindicate its adequacy for some PT infants.

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Antimicrobial effect of toothbrush with light emitting diode on dental biofilm attached to zirconia surface: an in vitro study (지르코니아 표면에 부착된 바이오필름에 대한 LED 치솔의 항균효과)

  • Park, Jong Hew;Kim, Yong-Gun;Um, Heung-Sik;Lee, Si Young;Lee, Jae-Kwan;Chang, Beom-Seok
    • Journal of Dental Rehabilitation and Applied Science
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    • v.35 no.3
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    • pp.160-169
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    • 2019
  • Purpose: The purpose of this study was to evaluate the antimicrobial effects of a toothbrush with light-emitting diodes (LEDs) on periodontitis-associated dental biofilm attached to a zirconia surface by static and dynamic methods. Materials and Methods: Zirconia disks (12 mm diameter, 2.5 mm thickness) were inserted into a 24-well plate (static method) or inside a Center for Disease Control and Prevention (CDC) biofilm reactor (dynamic method) to form dental biofilms using Streptococcus gordonii and Fusobacterium nucleatum. The disks with biofilm were subdivided into five treatment groups-control, commercial photodynamic therapy (PDT), toothbrush alone (B), brush with LED (BL), and brush with LED+erythrosine (BLE). After treatment, the disks were agitated to detach the bacteria, and the resulting solutions were spread directly on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy (SEM) was performed to visualize alterations in bacterial morphology. Results: No significant difference in biofilm formation was observed between dynamic and static methods. A significant difference was observed in the number of viable bacteria between the control and all experimental groups (P < 0.05). The percentage of bacterial reduction in the BLE group was significantly higher than in the other treated groups (P < 0.05). SEM revealed damaged bacterial cell walls in the PDT, BL, and BLE groups, but intact cell walls in the control and B groups. Conclusion: The findings suggest that an LED toothbrush with erythrosine is more effective than other treatments in reducing the viability of periodontitis-associated bacteria attached to zirconia in vitro.

Identification of LED Lights for the Attraction of Bemisia Tabaci and Effect of Host Plant in the Initial Periods (담배가루이 유인용 LED 선발과 기주식물이 초기 유인력에 미치는 영향)

  • Kwon, D.H.;Kwon, M.J.;Yang, D.Y.;Ahn, Y.K.;Hong, K.H.;Park, M.R.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.22 no.2
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    • pp.123-133
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    • 2020
  • Four LEDs (blue, green, red, and white light) were tested to identify the most attractive wave length to utilize as the forecasting tools for the B. tabaci in glass houses. Attractiveness was evaluated by the total number of the B. tabaci attached to a yellow sticky trap. In the condition of no host plant supplement, the attraction efficacy was ordered from high to low as blue light (107.3±2.5), white light (83.0±12.1), red light (58±21.8), and green light (39.7±8.1). In the supplement of the host plant, the attraction was observed in the order of blue light (52±17.4), red light (38.7±5.8), green light (12.7±1.5), and white light (11.7±5.0). In both experimental conditions, blue light showed the highest attraction. In terms of the host plant effect to LED attraction, it varied following as white light (85.9%), green light (68.1%), blue light (51.6%), and red light (33.3%). This result suggests that red light is the least affected by the host plant. In the evaluation of the relative control efficacy, it was determined following as red light (66.7%), blue light (48.5%), green light (31.9%) and white light (14.1%) (F3,8 = 14.7, P = 0.001). Taken together, blue light had a very high initial attraction, and red light was revealed low attraction effect by the supplement of the host plant. In field demonstration experiments, a high attractive efficacy was not observed due to low-temperature conditions, but similar higher attractive efficacy was observed in blue and red lights compared to the control. The commercialization of LEDs using red and blue in the future is expected to provide important information regarding B. tabaci population density forecast in glass house.

Antitumor activity of Trichosanthes kirilowii

  • Ryu, Shi-Yong;Lee, Seung-Ho;Lee, Sang-Un;Lee, Chong-Ock;No, Zaesung;Ahn, Jong-Woong
    • Archives of Pharmacal Research
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    • v.17 no.5
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    • pp.348-353
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    • 1994
  • The activity fractionation upon the MeOH extract of the root of trichosanthes kirilowii led to the isolation of eight cucurbitane tritepense namely cucurbitacin .betha. (I), isocucurbitacin .betha.(II), cucurbitacin D(III), isocucurbitacin D(IV), 3-epi-isocucurbitacin .betha(V), dihydrocucurbitain .betha. (VI), dihydroisocucurgbitachin .betha. (VII) and dihydrocucurbitacin E (VIII), as active principles. All isolates were shown to exhibit significant cytotoxicity against cultured human tumor cells, including A-549, Sk-OV-3, Sk-MEL-2, XF-498 and HCT 15, with an exceptionally high potency.

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A Study on Secure Encoding for Visible Light Communication Without Performance Degradation (가시광 통신에서 성능 저하 없는 보안 인코딩 연구)

  • Kim, Minchul;Suh, Taeweon
    • KIPS Transactions on Computer and Communication Systems
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    • v.11 no.1
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    • pp.35-42
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    • 2022
  • Visible light communication (VLC) is a method of transmitting data through LED blinking and is vulnerable to eavesdropping because the illumination affects the wide range of area. IEEE standard 802.15.7 defines On-Off Keying (OOK), Variable Pulse Position Modulation (VPPM), and Color Shift Keying (CSK) as modulation. In this paper, we propose an encryption method in VPPM for secure communication. The VPPM uses an encoding method called 4B6B where 16 different outputs are represented with 6-bit. This paper extends the number of outputs to 20, to add complexity while not violating the 4B6B generation conditions. Then each entry in the extended 4B6B table is scrambled using vigenère cipher. The probability of decrypting each 6-bit data is $\frac{1}{20}$. Eavesdropper should perform $\sum\limits_{k=1}^{n}20^k$ number of different trials to decrypt the message if the number of keys is n. The proposed method can be applied to OOK of PHY II and CSK of PHY III. We further discuss the secure encoding that can be used in OOK and CSK without performance degradation.