• Title/Summary/Keyword: Wave pattern

Search Result 930, Processing Time 0.027 seconds

Review of Newman-Sharma Wave Pattern Resistance Analysis Using Experimental and Computational Model Tests of KCS (KCS 선형의 모형시험 및 CFD 해석을 통한 Newman-Sharma 파형저항 추정법의 검토)

  • Myoungsoo Kim;Minchang Kim;Jeonghwa Seo;Woochan Seok
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.60 no.2
    • /
    • pp.76-85
    • /
    • 2023
  • The present study aims to review the wave pattern resistance analysis method suggested by the International Towing Tank Conference. From the experimental database of a container carrier ship model, the wave pattern measurement and resistance test results are utilized. The wave pattern resistance at the design Froude number is obtained to be compared with the wave making resistance of experiments. Wave pattern resistance is lower than wave making resistance by 1978 ITTC and uniform regardless of transverse location of wave cut. The method is also applied to the wave height field by Computational Fluid Dynamics (CFD) analyses with Froude number variation. Although numerical damping suppressed waves in downstream, waves around the hull and wave pattern resistance are properly predicted.

Study on th Wave-Pattern Analysis by Longitudinal Cut Method (Longitudinal Cut 파형해석의 응용을 위한 특성연구)

  • S.H.,Kang;Y.G.,Lee
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.18 no.1
    • /
    • pp.9-18
    • /
    • 1981
  • The wave-pattern analysis has been one of important research tools in the towing tank, and applied for hull form design. The longitudinal-cut method of Newman and Sharma is adopted in KRIS deep towing tank. Instrumentations and data acquisition systems are developed for that. Local effects and truncation effects are estimated by using calculated wave patterns of simple source distributions. Wigley model of 2m is used to check the accuracy of the whole system. Cut positions and truncation points are changed to investigate characteristics of the wave-pattern analysis. Coefficients of wave-pattern resistance are low-estimated in comparison with those of Maruo and Ikehata. The general quality of the system is very good, but some more efforts to increase the accuracy are required. Two full-form models(one basic form, the other with bulbous bow) are tested to show high application-possibilities of the wave-pattern analysis for the hull form design.

  • PDF

ATInSAR HOLOGRAM OBSERVATIONS OF COASTAL WAVE REFARCTION

  • Marghany, Maged
    • Proceedings of the KSRS Conference
    • /
    • 2003.11a
    • /
    • pp.438-440
    • /
    • 2003
  • This study is introducing a new approach of ATInSAR hologram for modeling wave refraction spectra pattern. TOPSAR data with L$_{-HH}$ and C-vv bands utilized spatial variation of wave refraction. Based on the phase information in along track interferometry, and ATInSAR hologram the quantitative information such swell wave height and spectra energy have been modeled. The phase information in ATInSAR hologram images can be transferred to wave refraction The ATInSAR hologram can be used to investigate the wave refraction pattern along the coastal waters. The fringe information pattern was shown to be useful in modeling wave refaction spectra varaition. The hologram interferometry wave refraction model consists of two sub-models. The purpose of first sub-model is to determine the swell wave height by using ATInSAR. Second sub-model aims to generate the holographic interferometry from the information of two wave spectra which detected by ATInSAR technique. The azimuth cut-off variations along the fringe patterns will be estimated. As azimuth cut-off contains the wave height information which could be used the significant wave height variation in convergence and divergence zone.

  • PDF

Study on the wave resonance-stimultion and receptionfor the BIO-KI (생체 기에 대한 피동공명적인 연구)

  • Ryu Gyeong Ho;Kim Gyeong Cheol;Lee Yong Tae
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.17 no.2
    • /
    • pp.263-274
    • /
    • 2003
  • The present condition of study on the wave-resonance for the bio-KI is observed. And the probroms of reception attendent on the stimulation of wave is observed centering around the sensory organ. The results is as follows: In the wave-resonant stand point, the tendency of studying on KI is showed in the several field all over the world. Because it is originated radionics, the wave-resonant tools of MRA insistenting minute-magnetism-resonance-apparatus need the more severe data in the side of electric circuit. The wave resonance apparatus according to the frequency occurance transmits low-frequency's vibration ratio to the electric stimulating aspect. The wave-water is considered on the application of wave-resonance transcription on the water, and needs the comprehension of torsion-field level. The wave-stimulation of the bio-KI and the reception of the sensory-organ is observed the connection of the sensory-organ and it's corresponding wave. The informations recorded in the wave are distinguished patternly. And the several shaping waves transmit the informations each other through the resonnance. The wave theory is explained the LEE(理) as the wave-pattern and the KI(氣) as the revelation of the patterned-wave in the LEE-KI theory(理氣論), moreover the SHIN(神) as the information of the wave-pattern and the KI as the energy of the wave and the JEUNG(精) as the material of the wave in the JEUNG-KI-SHIN theory(精氣神論). In this point, the study on the wave-resonance of bio-KI is thought that it is significantly in the study method for oriental medicine. The sum of the wave makes the moving body and forms the universe. It means that the several wave patterns gather and form new field. The pattern is a kind of the information and the information is not materially. The information of wave-pattern is the arrangement and the combination of the material source.

R Wave Detection and Advanced Arrhythmia Classification Method through QRS Pattern Considering Complexity in Smart Healthcare Environments (스마트 헬스케어 환경에서 복잡도를 고려한 R파 검출 및 QRS 패턴을 통한 향상된 부정맥 분류 방법)

  • Cho, Iksung
    • Journal of Korea Society of Digital Industry and Information Management
    • /
    • v.17 no.1
    • /
    • pp.7-14
    • /
    • 2021
  • With the increased attention about healthcare and management of heart diseases, smart healthcare services and related devices have been actively developed recently. R wave is the largest representative signal among ECG signals. R wave detection is very important because it detects QRS pattern and classifies arrhythmia. Several R wave detection algorithms have been proposed with different features, but the remaining problem is their implementation in low-cost portable platforms for real-time applications. In this paper, we propose R wave detection based on optimal threshold and arrhythmia classification through QRS pattern considering complexity in smart healthcare environments. For this purpose, we detected R wave from noise-free ECG signal through the preprocessing method. Also, we classify premature ventricular contraction arrhythmia in realtime through QRS pattern. The performance of R wave detection and premature ventricular contraction arrhythmia classification is evaluated by using 9 record of MIT-BIH arrhythmia database that included over 30 premature ventricular contraction. The achieved scores indicate the average of 98.72% in R wave detection and the rate of 94.28% in PVC classification.

Pattern Making of the Flared Skirt According to the Lower Body Somatotype of the 20's Women (20대 여성의 하반신 체형 유형에 따른 플레어스커트의 패턴 설계)

  • Lee, Youn-Soon;Ryu, Ji-Hyun;Kim, Kyung-A
    • Fashion & Textile Research Journal
    • /
    • v.10 no.5
    • /
    • pp.660-667
    • /
    • 2008
  • The purpose of this study was to modify a Flared Skirt for women according to the somatotype of lower body. The subjects for the wear test were 3 students, who were in $mean{\pm}1{\sigma}$ each somatotype. The results of this study are as follows: First, the Flared Skirt pattern was modified according to each type. The front waist line rising measurement proposed for type 1 and type 2 were 0.5cm, because of lower front silhouette with waist shape. The back waist line rising measurement proposed for type 2 was 1cm and type 3 was 0.5cm, because of lower back shape with hip. Second, the wave-height of nodes were regular at front and back in type 1. Also, the wave-height of nodes were evenly distributed side and center. The variation ratio of wave-height of back nodes were lower than existing pattern in type 2 and type 3. It means the variation ratio of wave-height of back nodes were regular in modification pattern. Altogether, modification patterns were more regular and lower than existing pattern in the number of nodes, the distribution ratio of nodes, the wave-height of node, the variation ratio of wave height of nodes.

Design of the Pattern Adjustable Base Station Antenna for WCDMA Applications

  • Lee, Sang-Ho;Lee, Jung-Nam;Lee, Don-Shin;Park, Jong-Kweon;Kim, Hak-Sun
    • Journal of electromagnetic engineering and science
    • /
    • v.8 no.2
    • /
    • pp.64-69
    • /
    • 2008
  • In this paper, we have proposed the pattern adjustable base station antenna for WCDMA applications. The proposed antenna consists of an omni-antenna(sleeve monopole) and two movable reflectors. The two reflectors can be controlled by mechanically and used to adjust the horizontal pattern of the base station antenna. The antenna was designed, fabricated, and measured. The antenna covers the entire WCDMA band for VSWR<1.4. The measured antenna gain is more than 15 dBi over the operating frequency range. By changing the angle (a) and the distance (d) of the antenna, the pattern adjustment of the proposed base station antenna is found to be possible.

Numerical Study on a Dominant Mechanism of Rip Current at Haeundae Beach: Honeycomb Pattern of Waves (수치모의를 통한 해운대 이안류의 주요 메커니즘 연구: 파랑의 벌집구조)

  • Choi, Junwoo;Park, Won Kyung;Bae, Jae Seok;Yoon, Sung Bum
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.32 no.5B
    • /
    • pp.321-329
    • /
    • 2012
  • Two regular progressive wave trains, the directions of which are slightly different from each other, develop a honeycomb pattern of wave crests due to their nonlinear interaction. In the honeycomb pattern of wave crest, the nodal line area, which has very low wave energy, is formed. When the honeycomb pattern is developed near the beach area, rip current evolves through the nodal line area formed in the cross shore direction. In this study, to confirm that the formation of honeycomb pattern of waves near the beach area is a dominant mechanism of rip current occurred at Haeundae beach, we performed a numerical simulation of nearshore circulation at Haeundae beach under an unidirectional and monochromatic wave condition by using a nonlinear Boussinesq equation model. As a result, wave refraction due to topographical characteristics (i.e., submerged shoal) of Haeundae gave rise to several wave trains propagating with slightly different directions toward the beach, and consequently rip currents well developed through the nodal line area of honeycomb patterns of wave crest. In addition, we found that a narrow-banded spectral wave condition (i.e., a swell spectrum) increases more likelihood of rip current than a broad-banded spectral wave condtion based on the simulations employing various wave spectra with an equivalent wave height and period.

Finite Element Analysis on Standing Wave Phenomenon of a Tire Considering Tread Pattern (트레드 패턴을 고려한 타이어의 스탠딩 웨이브 현상에 대한 유한 요소 해석)

  • Kim, Kee-Woon;Jeong, Hyun-Sung
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.14 no.2
    • /
    • pp.76-83
    • /
    • 2006
  • Each tire has a critical speed at which a standing wave phenomenon occurs along the circumferential direction. If the standing waves are formed, the tire temperature is rapidly increased and it leads to tire failure eventually. As the formation of the standing waves is closely related to the tire stiffness, the effect of the tread pattern needs to be studied numerically. The standing wave phenomenon of a tire model with tread pattern is predicted by an explicit finite element method. The critical speed of the tire with tread pattern is in a good agreement with the experiment and is $15{\sim}20\;km/h$ lower than that of the tire without tread pattern. The effects of the inflation pressure and the vertical load on the critical speed are also investigated by using the tire model with tread pattern.

Relationship between the Spatial Allocation of Developed Area and the Heat Wave Phenomenon: The Case of Five Metropolitan Cities (시가화지역 공간상 위치분배와 폭염현상과의 관계성: 5개 광역시 사례)

  • Kang, Sangjun
    • Journal of Environmental Impact Assessment
    • /
    • v.30 no.3
    • /
    • pp.175-185
    • /
    • 2021
  • To better understand the heat wave phenomenon in the urban areas, it is desirable to explore the relationship between spatial allocation of land use and the heat wave. The purpose of this paper is to investigate the ranking correlation between heat wave days and developed types, specifically, core and islet developments. The methods employed are morphological spatial pattern, spatial autocorrelation, and spearman ranking correlation analyses by using the 30-year annual heat wave day records forthe five metropolitans. This research indicates that a fragmented development pattern including islets has mostly negative effects to the urban heat wave phenomenon. It means there is a relation between development pattern and heat wave.