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DCI Based Watermarking for Image Verification and Authentication (인증과 무결성을 위한 DCT 기반 워터마킹)

  • 이혜란;박지환
    • Proceedings of the Korea Multimedia Society Conference
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    • 2001.06a
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    • pp.506-509
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    • 2001
  • 본 논문에서는 디지털 영상의 변조를 확인함과 동시에 변조의 위치를 확인하는 DCT 기반의 fragile watermarking을 제안한다. 디지털 영상의 인증과 무결성을 위해 기존의 Wong이 사용한 해쉬 함수와 비대칭키 암호 알고리즘을 사용하며, 영상에 DCT 변환을 함으로서 영상의 모든 픽셀에 워터마크를 삽입하지 않고서도 변조의 유무를 확인하는 것이 가능하다. 본 논문에서는 DCT 계수 중 일부 저주파 계수의 하위 비트에 워터마크를 삽입하여 워터마크의 비가시성과 연성을 만족하며 변조의 유무와 위치를 확인한 수 있게 된다.

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A Fast Analysis on Floating Wave Energy Conversion System (부유식 파랑 에너지 변환 시스템의 단순화된 열역학적 해석법)

  • Lee, Sang-Moo;Kim, Seoung-Gun
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4 s.35
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    • pp.159-168
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    • 1999
  • 부유식 파랑에너지 변환시스템(Oscillating Water Column)에 대한 해석은 입력파와 챔버, 챔버내 공기의 상호작용으로 인하여 어려움이 많다. 이 논문은 이와 같은 요소를 고려하면서도 쉽고 간편한 해석법을 제시한다. 파랑에너지에 의한 자가발전은 파랑에너지를 기계적 운동으로 변환하고 이를 전기에너지로 변환함으로써 가능하다. 본 논문은 파랑에너지에서 기계적 에너지로 변환하는 과정에 집중하여 그 부분의 성능을 해석한다. 단일 진동수 규칙파가 입력되었을 때에 파에 의하여 챔버의 상하운동이 선형적으로 발생하는 것으로 보며, 이 상하운동에 챔버내의 압력 영향을 고려하였다. 상하운동과 챔버내로 투과한 파, 그리고 챔버내 압력에 의해 발생되는 파에 의해 챔버내의 상대운동을 정하고, 그 상대 운동에 의한 공기의 압축 팽창과 온도상승을 근사적 열역학적 방정식으로 해석하였고 오리피스를 통한 유량을 결정하였다. 얻어진 식은 간단하면서도 관련요소의 영향을 전반적으로 표현한다. 결과에 따르면 고정식의 에너지 변환식은 부유식의 특별한 경우로서 파악되었다. 또한 고정식의 시스템을 그대로 부유식으로 바꿨을 때 그 변환효율은 적어지는 것으로 나타났다. 본 해석법은 계산이 간편하므로 설계단계에서 유용하게 활용될 수 있을 것으로 기대된다.

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The study on Harmonic Current Generated on Power Supply Station in(for) Conventional line and The Review on Effect of facility reducing Harmonic Current. (기존선 변전소에서의 고조파 발생현황과 저감설비 설치 효과 검토)

  • Park Sang-Ock;Lee Jong-Woo;Kwon Sam-Young;Lee Chang-Moo
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1309-1315
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    • 2004
  • The harmonic current originated from electric cars will be cause of electromagnetic interference along adjacent communication cables and troubles with signaling. It will also cause overheating in power capacitor and malfuction in protection relay. Therefore, it brought actual measurement of harmonic current by each operation mode. Because the result exceeded the value prescribed by Korea Electric Power Corporation, we constructed facilities reducing harmonic current on overloaded part at each power supply station located in conventional line (Guro, Kyungsan, and Milyang) as an optimal alternative. Then, this study compared and analyzed the reducing effect before and after constructing facility.

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Comparisons of Growth, Heading and Grain Filling Characteristics between Wet-hill-seeding and Transplanting in Rice (벼 무논점파재배와 이앙재배의 생육, 출수 및 등숙특성 비교)

  • Shon, Ji-Young;Lee, Chung-Kuen;Kim, Jun-Hwan;Yoon, Young-Hwan;Yang, Won-Ha;Choi, Kyung-Jin;Choi, Min-Gyu;Park, Hong-Kyu;Ko, Jong-Cheol;Kim, Yeon-Gyu;Kim, Chung-Kon;Yang, Woon-Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.57 no.2
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    • pp.151-159
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    • 2012
  • Direct seeding of rice is a time- and laborsaving method, compared to machine transplanting. However, the area planted to direct-seeded rice is decreasing because of instability of seedling establishment, lodging, occurrence of weedy rice, and deterioration of grain quality. A newly developed wet-hill-seeding of rice, a type of direct seeding method, has shown features of growth similar to machine transplanted rice. This study was carried out to compare tillering pattern, heading characteristics and grain filling traits between transplanting and wet-hill-seeding in rice. Tillering of wet-hill-seeded rice was more vigorous than that of transplanted rice showing maximum tiller number 30~100% higher than transplanted rice. Wet-hill seeded rice showed later heading and shorter heading duration than transplanted rice. To find out the relationship between heading characteristics and grain filling traits, every panicle was tagged for flowering date, and the panicles on each heading date were inspected for grain filling traits. Wet-hill seeded rice and transplanted rice exhibited no significant difference in culm length, panicle length, the percentage of grain filling and perfect brown rice on each heading date during total heading period. Therefore, we conclude that wet-hill-seeding method is not inferior to machine transplanting in terms of seedling establishment, growth, grain filling and head rice yield.

Quality Characteristics of Kimchis with different Ingredients (재료를 달리한 김치의 품질)

  • Kim, Myung-Hee;Shin, Mal-Sik;Jhon, Deok-Young;Hong, Yoon-Ho;Lim, Hyun-Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.16 no.4
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    • pp.268-277
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    • 1987
  • The changes of the aerobic viable bacterial counts, the content of chemical components and the sensory evaluation in Kimchis which were prepared with Various ingredients (red pepper, green onion, garlic and ginger) and fermentation at $20^{\circ}C$ were investigated. Aerobic viable bacterial counts were suddenly decreased with fermentation, but it was decreased slowly from the second day. Salinity of Kimchis was $1.8%{\sim}2.0%$ and titratable acidify were lower in sample 2 (deleted red pepper) and 3 (deleted green onion) on the first day but sample 4 (deleted garlic) after the fifth day. Total sugar content was decreased from $1.8{\sim}2.7g/100g$ to $0.8{\sim}1.1g/100g$ during fermentation periods. Carbon dioxide content maintained relatively higher in sample 2 and 5 (deleted ginger) with fermentation. Volatile organic acid content showed no difference in all Kimchis with fermentation. During the whole fermentation period, appearance was the worst in sample 2. Texture, off-flavor and overall-eating quality were the worst in sample 4. Carbonated flavor and overall eating quality were the best in sample 5.

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A Hydraulic Model Test of Wave Transformation in the Surf Zone (쇄파대에서의 파랑 변형에 대한 수리모형실험)

  • 정신택;채장원;정원무
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.3 no.3
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    • pp.163-169
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    • 1991
  • Sixty seven regular wave tests were performed in a wave-current flume to investigate proper-ties of waves breaking on irregular slope profiles. In these tests, 1/10, 1/20 beach slopes were made using angles and plywoods. A little differences were found in such properties as breaker depth and height indices. runup for plane slopes comparing with other laboratory experiments. however. for smaller deepwater wave steepness, measured breaker height and depth data values were smaller than other formulas. On wave runup agreement was good between experiments and Hunt formula. however. measured data values were influenced by number of breaking. Significant differences were found in breaker depth index for plane and barred slopes. Wave height decay after breaking was found to be smaller than Dally et al.'s formula (1984).

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A Study on a Shorting Pin and Slot-Loaded Antenna for Harmonic Suppression (고조파 억압을 위한 단락핀-슬롯 적재 안테나에 관한 연구)

  • 권세웅;이성호;이병무;김형락;윤영중
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.8
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    • pp.811-818
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    • 2002
  • In this paper, a shorting pin and slot-loaded microstrip patch antenna is designed and fabricated. A shorting pin and slots are used for harmonic suppression on an inset fed antenna. A shorting pin and slot properties are analyzed by cavity model of the rectangular patch and the characteristics of the designed antenna are described. The designed antenna provides a gain of 7 dBi at the fundamental frequency, 5.8 GHz. In the second and third harmonic frequencies, the proposed antenna has gain suppression properties of -3.3 dB and -14.3 dB at each harmonic frequency, respectively.

Detection of a Crack on a Plate by IDT Type Lamb Wave Sensors (IDT형 Lamb 파 센서에 의한 판상의 균열 검출)

  • Kim, Jun-Ho;Roh, Yong-Rae
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.8
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    • pp.483-490
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    • 2010
  • In this paper, an Inter-Digital Transducer (IDT) type Lamb wave sensor is proposed to estimate the geometry and number of cracks on a plate structure, and its validity is checked through experiments. This IDT type sensor is more readily controllable than conventional patch type piezoelectric sensors to modify its operation frequency and directionality by altering its finger patterns. In this work, omni-directional annular IDT and highly directional rectangular IDT sensors are designed and fabricated. The IDT sensors are used to diagnose the length, number and orientation of cracks on an aluminum plate by measuring the amplitude and time of flight of Lamb waves. The results are analyzed to discuss the efficacy of the IDT sensors.

Impact of Shock Wave on Nerve Regeneration in Motion Analysis of Affected Side after Nerve Injury (신경 손상 후 환측의 동작분석을 통한 충격파가 신경재생에 미치는 영향)

  • Lee, Jung-Ho;Choi, Yeong-Deok;Sung, Youn-Bum
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.9 no.3
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    • pp.533-540
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    • 2019
  • This study investigated the effect of extracorporeal shock wave therapy on nerve regeneration in nerve injured rats. In this study, we used 30 male Sprague-Dawley rats weighing 230-280g and 6 weeks old. Study groups were divided into two groups using a random sampling method: experimental group (n=15) treated with extracorporeal shock wave after sciatic nerve injury and control group (n=15) treated without extracorporeal shock wave after sciatic nerve injury. In this study, extracorporeal shock wave therapy equipment (OPTIMUS, SALUS TALENT 3, Korea) was used to apply extracorporeal shock wave therapy and applied to the sciatic nerve crush area of the right hind limb using low intensity. We measured the stance time and stride distance of the affected side using dartfish software. There was a statistically significant difference in the change of stance time and stride distance of the affected side between the experimental group using extracorporeal shock wave therapy and the control group without extracorporeal shock wave treatment. In conclusion, extracorporeal shock wave therapy has a positive effect on nerve regeneration.

Antioxidant and Antimicrobial Activities of Ethanol Extract from Six Vegetables Containing Different Sulfur Compounds (황 함유 채소 에탄올 추출물의 항산화 및 항균활성)

  • Kim, Kyoung-Hee;Kim, Hye-Joung;Byun, Myung-Woo;Yook, Hong-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.41 no.5
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    • pp.577-583
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    • 2012
  • This study investigated the antioxidant activities, and antimicrobial activity $in$ $vitro$ of an 80% ethanol extract from garlic, daikon, leek, ginger, onion, and green onion, which are widely-used ingredients in Korean food that contain sulfur. The total polyphenol content in ginger and leek extracts showed a high value ($233.63{\pm}4.59$ and $220.98{\pm}10.56$ mg/g GAE) and onions, leeks, garlic, and daikon followed by with $69.07{\pm}1.42$, $68.83{\pm}2.11$, $19.41{\pm}0.40$, $19.05{\pm}03.32$ mg/g GAE, respectively. DPPH radical scavenging activity was highest with ginger extracts ($1.57{\pm}0.15$ mg/mL as $IC_{50}$) followed in order of decreasing activity by leeks, onions, daikon, green onions, and garlic. The results of ABTS radical scavenging activity and FRAP value showed higher antioxidant activity in extracts from ginger and leek. The order of vegetables with most to least prevalent ABTS radical scavenging activity was green onions, onions, garlic, and finally daikon. From greatest to least FRAP value, the relevant vegetables were green onions, onions, daikon, and garlic (p<0.05). Ginger extracts showed promise against seven strains of microbes: $Bacillus$ $cereus$, $Bacillus$ $subtillis$, $Staphylococcus$ $aureus$, $Lactobacillus$ $plantarum$, $Escherichia$ $coli$, $Salmonella$ $enterica$, and $Pseudomonas$ $aeruginosa$. Garlic extracts (5 mg/disc) showed strong antimicrobial activity against $B.$ $cereus$ (22.3 mm) and $E.$ $coli$ (24.3 mm). Extracts of both onion and green onion showed antimicrobial activity against only $E.$ $coli$ (12.7 and 10.3 mm) and $B.$ $cereus$ (12.0 and 12.5 mm) at 10 mg/disc, and the inhibition zone diameter from extracts of garlic and leeks were 18.0 mm and 10.4 mm vs. $L.$ $plantarum$ at 10 mg/disc. This study showed positive antioxidant activities for ginger and leeks, and positive antimicrobial activities for leeks and garlic. These sulfur-containing vegetables are widely used in Korean food. Leeks especially could serve as a functional food preservative.