• Title/Summary/Keyword: four-dimensional

Search Result 1,755, Processing Time 0.033 seconds

A Study on the Digital Decipherment of the Goguryeo Stele in Chungju (충주고구려비(忠州高句麗碑) 디지털 판독의 성과와 고찰)

  • JO, Younghoon;KWON, Dakyung;AHN, Jaehong;KO, Kwangeui
    • Korean Journal of Heritage: History & Science
    • /
    • v.54 no.2
    • /
    • pp.240-253
    • /
    • 2021
  • Various decipherment technologies, including manual rubbing, have been continuously applied to the Goguryeo Stele in Chungju. However, an official document for advanced decipherment is required as there remain characters to be deciphered. This study focuses on interdisciplinary digital decipherment using digital visualization results based on reflectance transformation imaging and three-dimensional scanning. On that basis, the joint decipherment document in 2019 is classified into eight types according to character changes from 1979 to 2000, and decipherment achievements are discussed. Important outcomes of the joint decipherment document include a new interpretation of four existing characters and the identification of 28 new characters. Additionally, 68 characters on the front face and 20 on the left face, which are listed differently in previous decipherment documents, are determined to be a single character through a consensus process. Compared to the previous decipherment document, the "decision" character is increased by a total of 89 characters (22.6%), and the "different opinion" character is decreased by 126 characters (32.0%). Thus, this digital decipherment greatly contributes to the reexamination of the Goguryeo Stele in Chungju and complements the previous decipherment document through reflectance transformation imaging and three-dimensional scanning. However, continuous research is necessary to enhance decipherment rates, since 123 characters (31.3%) are yet to receive decipherment. In the future, decipherment advancement regarding the Goguryeo Stele in Chungju should be based on convergence research between the humanities and science. Furthermore, it seems that researchers must make constant efforts to apply new imaging analysis technology and to develop customized technology for decipherment.

3-D Finite element stress analysis in screw-type, cement-type, and combined-type implant fixed partial denture designs (임플란트 상부보철물의 유지형태에 따른 3차원 유한요소 응력분석)

  • Lee, Sung-Chun;Kim, Seok-Gyu
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.47 no.4
    • /
    • pp.365-375
    • /
    • 2009
  • Statement of problems: Stress analysis on implant components of the combined screw- and cement-retained implant prosthesis has not investigated yet. Purpose: The purpose of this study was to assess the load distribution characteristics of implant prostheses with the different prosthodontic retention types, such as cement-type, screw-type and combined type by using 3-dimensional finite element analysis. Material and methods: A 3-dimensional finite element model was created in which two SS II implants (Osstem Co. Ltd.) were placed in the areas of the first premolar and the first molar in the mandible, and three-unit fixed partial dentures with four different retention types were fabricated on the two SS II implants. Model 1 was a cement-retained implant restoration made on two cement-retained type abutments (Comocta abutment; Osstem Co. Ltd.), and Model 2 was a screw-retained implant restoration made on the screw-retained type abutments (Octa abutment; Osstem Co. Ltd.). Model 3 was a combined type implant restoration made on the cement-retained type abutment (Comocta abutment) for the first molar and the screw-retained type abutment (Octa abutment) for the first premolar. Lastly, Model 4 was a combined type implant restoration made on the screw-retained type abutment (Octa abutment) for the first molar and the cement-retained type abutment (Comocta abutment) for the first premolar. Average masticatory force was applied on the central fossa in a vertical direction, and on the buccal cusp in a vertical and oblique direction for each model. Von-Mises stress patterns on alveolar bone, implant body, abutment, abutment screw, and prosthetic screw around implant prostheses were evaluated through 3-dimensional finite element analysis. Results: Model 2 showed the lowest von Mises stress. In all models, the von Mises stress distribution of cortical bone, cancellous bone and implant body showed the similar pattern. Regardless of loading conditions and type of abutment system, the stress of bone was concentrated on the cortical bone. The von-Mises stress on abutment, abutment screw, and prosthetic screw showed the lower values for the screw-retained type abutment than for the cement-retained type abutment regardless of the model type. There was little reciprocal effect of the abutment system between the molar and the premolar position. For all models, buccal cusp oblique loading caused the largest stress, followed by buccal cusp vertical loading and center vertical loading. Conclusion: Within the limitation of the FEA study, the combined type implant prosthesis did not demonstrate more stress around implant components than the cement type implant prosthesis. Under the assumption of ideal passive fit, the screw-type implant prosthesis showed the east stress around implant components.

Documentation of Intangible Cultural Heritage Using Motion Capture Technology Focusing on the documentation of Seungmu, Salpuri and Taepyeongmu (부록 3. 모션캡쳐를 이용한 무형문화재의 기록작성 - 국가지정 중요무형문화재 승무·살풀이·태평무를 중심으로 -)

  • Park, Weonmo;Go, Jungil;Kim, Yongsuk
    • Korean Journal of Heritage: History & Science
    • /
    • v.39
    • /
    • pp.351-378
    • /
    • 2006
  • With the development of media, the methods for the documentation of intangible cultural heritage have been also developed and diversified. As well as the previous analogue ways of documentation, the have been recently applying new multi-media technologies focusing on digital pictures, sound sources, movies, etc. Among the new technologies, the documentation of intangible cultural heritage using the method of 'Motion Capture' has proved itself prominent especially in the fields that require three-dimensional documentation such as dances and performances. Motion Capture refers to the documentation technology which records the signals of the time varing positions derived from the sensors equipped on the surface of an object. It converts the signals from the sensors into digital data which can be plotted as points on the virtual coordinates of the computer and records the movement of the points during a certain period of time, as the object moves. It produces scientific data for the preservation of intangible cultural heritage, by displaying digital data which represents the virtual motion of a holder of an intangible cultural heritage. National Research Institute of Cultural Properties (NRICP) has been working on for the development of new documentation method for the Important Intangible Cultural Heritage designated by Korean government. This is to be done using 'motion capture' equipments which are also widely used for the computer graphics in movie or game industries. This project is designed to apply the motion capture technology for 3 years- from 2005 to 2007 - for 11 performances from 7 traditional dances of which body gestures have considerable values among the Important Intangible Cultural Heritage performances. This is to be supported by lottery funds. In 2005, the first year of the project, accumulated were data of single dances, such as Seungmu (monk's dance), Salpuri(a solo dance for spiritual cleansing dance), Taepyeongmu (dance of peace), which are relatively easy in terms of performing skills. In 2006, group dances, such as Jinju Geommu (Jinju sword dance), Seungjeonmu (dance for victory), Cheoyongmu (dance of Lord Cheoyong), etc., will be documented. In the last year of the project, 2007, education programme for comparative studies, analysis and transmission of intangible cultural heritage and three-dimensional contents for public service will be devised, based on the accumulated data, as well as the documentation of Hakyeonhwadae Habseolmu (crane dance combined with the lotus blossom dance). By describing the processes and results of motion capture documentation of Salpuri dance (Lee Mae-bang), Taepyeongmu (Kang seon-young) and Seungmu (Lee Mae-bang, Lee Ae-ju and Jung Jae-man) conducted in 2005, this report introduces a new approach for the documentation of intangible cultural heritage. During the first year of the project, two questions have been raised. First, how can we capture motions of a holder (dancer) without cutoffs during quite a long performance? After many times of tests, the motion capture system proved itself stable with continuous results. Second, how can we reproduce the accurate motion without the re-targeting process? The project re-created the most accurate motion of the dancer's gestures, applying the new technology to drew out the shape of the dancers's body digital data before the motion capture process for the first time in Korea. The accurate three-dimensional body models for four holders obtained by the body scanning enhanced the accuracy of the motion capture of the dance.

EEPERF(Experiential Education PERFormance): An Instrument for Measuring Service Quality in Experiential Education (체험형 교육 서비스 품질 측정 항목에 관한 연구: 창의적 체험활동을 중심으로)

  • Park, Ky-Yoon;Kim, Hyun-Sik
    • Journal of Distribution Science
    • /
    • v.10 no.2
    • /
    • pp.43-52
    • /
    • 2012
  • As experiential education services are growing, the need for proper management is increasing. Considering that adequate measures are an essential factor for achieving success in managing something, it is important for managers to use a proper system of metrics to measure the performance of experiential education services. However, in spite of this need, little research has been done to develop a valid and reliable set of metrics for assessing the quality of experiential education services. The current study aims to develop a multi-item instrument for assessing the service quality of experiential education. The specific procedure is as follows. First, we generated a pool of possible metrics based on diverse literature on service quality. We elicited possiblemetric items not only from general service quality metrics such as SERVQUAL and SERVPERF but also from educational service quality metrics such as HEdPERF and PESPERF. Second, specialist teachers in the experiential education area screened the initial metrics to boost face validity. Third, we proceeded with multiple rounds of empirical validation of those metrics. Based on this processes, we refined the metrics to determine the final metrics to be used. Fourth, we examined predictive validity by checking the well-established positive relationship between each dimension of metrics and customer satisfaction. In sum, starting with the initial pool of scale items elicited from the previous literature and purifying them empirically through the surveying method, we developed a four-dimensional systemized scale to measure the superiority of experiential education and named it "Experiential Education PERFormance" (EEPERF). Our findings indicate that students (consumers) perceive the superiority of the experiential education (EE) service in the following four dimensions: EE-empathy, EE-reliability, EE-outcome, and EE-landscape. EE-empathy is a judgment in response to the question, "How empathetically does the experiential educational service provider interact with me?" Principal measures are "How well does the service provider understand my needs?," and "How well does the service provider listen to my voice?" Next, EE-reliability is a judgment in response to the question, "How reliably does the experiential educational service provider interact with me?" Major measures are "How reliable is the schedule here?," and "How credible is the service provider?" EE-outcome is a judgmentin response to the question, "What results could I get from this experiential educational service encounter?" Representative measures are "How good is the information that I will acquire form this service encounter?," and "How useful is this service encounter in helping me develop creativity?" Finally, EE-landscape is a judgment about the physical environment. Essential measures are "How convenient is the access to the service encounter?,"and "How well managed are the facilities?" We showed the reliability and validity of the system of metrics. All four dimensions influence customer satisfaction significantly. Practitioners may use the results in planning experiential educational service programs and evaluating each service encounter. The current study isexpected to act as a stepping-stone for future scale improvement. In this case, researchers may use the experience quality paradigm that has recently arisen.

  • PDF

The Effect of After-school Programs on Science-related Attitude and Learning Achievement of High School Students : In the Unit of 'The Change of Weather' (방과후 학교 프로그램이 고등학교 학생들의 과학에 대한 태도와 학업성취도에 미치는 영향 : '날씨의 변화' 단원을 중심으로)

  • Keum, Kyung-Jin;Yoon, Ill-Hee
    • Journal of Science Education
    • /
    • v.32 no.2
    • /
    • pp.71-86
    • /
    • 2008
  • The purpose of this study was to apply After-school programs related to sub-chapter 'The Change of Weather', and thereby to investigate the effect of After-school program on science-related attitude and learning achievement of students, and interaction between treatment methods and students' learning ability. The subjects of study consisted of 2nd grade students of sixty four students in high school. Sixty four students were divided into two categories by experimental and control groups on the basis of midterm examination before teaching treatment. The experimental groups have received four After-school programs including making models of a weather front, measurement of wind, measurement of temperature and the dew point, making a three-dimensional weather chart which were developed by researcher for six times. The control groups have received the instruction through the conventional teaching methods. Seventy questions within seven frameworks of TOSRA have been used in this study as an evaluation instrument of science-related attitude. Learning achievement has been evaluated using an instrument developed by researcher. The scores of both pre-test and post-test were estimated by ANCOVA. The results of this study can be summarized as follows. (1) After-school programs were more effective in progressing the three categories of science related attitude of high school students i.e. pleasure of science class(p<.05), reception of scientific attitude(p<.01), attitude about a science research(p<.05) than conventional teaching methods. (2) Experimental groups showed statistically significant improvement on learning achievement than control groups(p<.05). (3) The effect of treatment methods on students' learning ability has been improved in experimental groups more positively than control groups(p<.05). High level students in experimental groups showed significant improvement on learning achievement than low level students according to the representing profile plot. But there were no significant interaction between treatment methods and students' learning ability(p>.05) In conclusion, the After-school programs have positive effect on the improvement of science related attitude and learning achievement.

  • PDF

Effect of Clothing cues and perceiver variables on Impression Formation of Female dressed in Korean Dress(Part I) - Focus on Clothing Cues - (의복단서, 지각자변인이 여자한복착용자의 인상형성에 미치는 영향(I) - 의복단서를 중심으로 -)

  • 박찬부
    • Journal of the Korean Society of Costume
    • /
    • v.32
    • /
    • pp.313-336
    • /
    • 1997
  • Nineteen stimulus photograghs varied in hue and color scheme of one clothing style of Korean dress worn by a female were used to investigate the effect of color color scheme and structure on impression formation for Korean dress. Subjects were 77 male and 86 female undergraduate and graduate students. The stimuli c9onsisted of two sets(cool and warm) of four similar color schemes two sets (cool and warm in Chima color) of five contrasting color schemes and one extra stimulus triad 3 hue base. Structures were de-fined by color schemes of Kit.Korum toward the color schemes of Jokori and Chima. Stimu-lus photogragh selected from Korean dress fashion magazines was managed and varied in hues and color schemes to Kit Korum Jokori and Chima according to Korean Standard Color through scanning and Adobe photoshop 3.0 program and then pictured through slide printer(HR-6000). Each subject assessed 19 stimulus color photographs with incorporated 7 point semantic differential response scale. The data were analyzed by frequency mean factor analysis t-test ANOVA and Scheffe test. Results indicate impression ofrmations are af-fected by clothing cues. 1) Four factors emerged to account for dimensional structure of impressions of female features on Korean dress. These four factors were titled as(1) preference.evaluation (2) individuality.attention (3) youth and (4) friendshio. The preference.evaluation factor was the largest including eleven adjectives and accounting for 29.62% of the variances. 2) Almost every clothing cue(color, color scheme, structure) had some effects on im-pressions formed But the color of Chima did not form the effects on impression of prefer-ence.evaluation factor. The effect of related color scheme was the most influential clothing cue on impressions of preference.evalation factor and friendship factor whereas the ef-fect of contrasting color scheme was the most influential clothing cue on impressions of indi-viduality.attention factor and youth factor. The effect of cool color of Chima was the most influential clothing cue on impression of indi-viduality.attention factor whereas the effect of warm color of Chima was the most influen-tial clothing cue on impressions of youth factor and friendship factor. The effect of Jokori/Chima.Kit.Korum structure was the most influential clothing cue on impressions of pref-erence.evaluation factor and youth factor whereas the effect of Kit.Korum/Jokori.Chima structure was the most influential clothing cue on impressions of individuality.attention factor and friendship factor. 3) The interaction effects were appeared among clothing cues. Significant interaction effects between color schemes(similar and contrasting) and colors of Chima(cool and warm were appeared on impressions of prefer-ence.evaluation factor imdividuality.atten-tion factor and friendship factor, Significant interaction effects between color schemes (similar and contrasting) and structures (Jokori.Chima.Kit.Korum; Jokori.Kit.Koru-m/Chima;Jokori/Chima.Kit.Korum;Kit.Korum/Jokori.Chima) were appeared on impressions of preference.evaluation factor youth factor and friendship factor. Signifi-cant interaction effects between colors(cool and warm) and structures were appeared on impressions of individuality.attention factor youth factor and friendship factor. Sighifi-cant interaction effects between colors(cool and warm) and structures were appeared on impressions of individuality.attention factor youth factor and friendship factor. Significant interaction effects among clothing cues(color color schemes and structures) were appeared on all impression factors. The friendship factor was the most friquently affected impression factor by interaction effects among clothing cues. In summary the clothing was used as nonverbal cues in the effect on impression for-mation of female dressed in Korean dress. it concluded that color schemes worked as cen-tral traits and colors of Chima and structures worked as peripheral traits in the formation of impression of the female clothed in Korean dress. hence organizing our impressions with respect to the parts of the Korean dress in re-lation to the whole holistic perceptual pro-cess Gestalt approach was used and supported.

  • PDF

Evaluation of the Positional Uncertainty of a Liver Tumor using 4-Dimensional Computed Tomography and Gated Orthogonal Kilovolt Setup Images (사차원전산화단층촬영과 호흡연동 직각 Kilovolt 준비 영상을 이용한 간 종양의 움직임 분석)

  • Ju, Sang-Gyu;Hong, Chae-Seon;Park, Hee-Chul;Ahn, Jong-Ho;Shin, Eun-Hyuk;Shin, Jung-Suk;Kim, Jin-Sung;Han, Young-Yih;Lim, Do-Hoon;Choi, Doo-Ho
    • Radiation Oncology Journal
    • /
    • v.28 no.3
    • /
    • pp.155-165
    • /
    • 2010
  • Purpose: In order to evaluate the positional uncertainty of internal organs during radiation therapy for treatment of liver cancer, we measured differences in inter- and intra-fractional variation of the tumor position and tidal amplitude using 4-dimentional computed radiograph (DCT) images and gated orthogonal setup kilovolt (KV) images taken on every treatment using the on board imaging (OBI) and real time position management (RPM) system. Materials and Methods: Twenty consecutive patients who underwent 3-dimensional (3D) conformal radiation therapy for treatment of liver cancer participated in this study. All patients received a 4DCT simulation with an RT16 scanner and an RPM system. Lipiodol, which was updated near the target volume after transarterial chemoembolization or diaphragm was chosen as a surrogate for the evaluation of the position difference of internal organs. Two reference orthogonal (anterior and lateral) digital reconstructed radiograph (DRR) images were generated using CT image sets of 0% and 50% into the respiratory phases. The maximum tidal amplitude of the surrogate was measured from 3D conformal treatment planning. After setting the patient up with laser markings on the skin, orthogonal gated setup images at 50% into the respiratory phase were acquired at each treatment session with OBI and registered on reference DRR images by setting each beam center. Online inter-fractional variation was determined with the surrogate. After adjusting the patient setup error, orthogonal setup images at 0% and 50% into the respiratory phases were obtained and tidal amplitude of the surrogate was measured. Measured tidal amplitude was compared with data from 4DCT. For evaluation of intra-fractional variation, an orthogonal gated setup image at 50% into the respiratory phase was promptly acquired after treatment and compared with the same image taken just before treatment. In addition, a statistical analysis for the quantitative evaluation was performed. Results: Medians of inter-fractional variation for twenty patients were 0.00 cm (range, -0.50 to 0.90 cm), 0.00 cm (range, -2.40 to 1.60 cm), and 0.00 cm (range, -1.10 to 0.50 cm) in the X (transaxial), Y (superior-inferior), and Z (anterior-posterior) directions, respectively. Significant inter-fractional variations over 0.5 cm were observed in four patients. Min addition, the median tidal amplitude differences between 4DCTs and the gated orthogonal setup images were -0.05 cm (range, -0.83 to 0.60 cm), -0.15 cm (range, -2.58 to 1.18 cm), and -0.02 cm (range, -1.37 to 0.59 cm) in the X, Y, and Z directions, respectively. Large differences of over 1 cm were detected in 3 patients in the Y direction, while differences of more than 0.5 but less than 1 cm were observed in 5 patients in Y and Z directions. Median intra-fractional variation was 0.00 cm (range, -0.30 to 0.40 cm), -0.03 cm (range, -1.14 to 0.50 cm), 0.05 cm (range, -0.30 to 0.50 cm) in the X, Y, and Z directions, respectively. Significant intra-fractional variation of over 1 cm was observed in 2 patients in Y direction. Conclusion: Gated setup images provided a clear image quality for the detection of organ motion without a motion artifact. Significant intra- and inter-fractional variation and tidal amplitude differences between 4DCT and gated setup images were detected in some patients during the radiation treatment period, and therefore, should be considered when setting up the target margin. Monitoring of positional uncertainty and its adaptive feedback system can enhance the accuracy of treatments.

Distortion of the Dose Profile in a Three-dimensional Moving Phantom to Simulate Tumor Motion during Image-guided Radiosurgery (방사선수술에서 종양 움직임을 재현시킨 움직이는 팬텀을 이용하여 선량 분포의 왜곡에 대한 연구)

  • Kim, Mi-Sook;Ha, Seong-Hwan;Lee, Dong-Han;Ji, Young-Hoon;Yoo, Seong-Yul;Cho, Chul-Koo;Yang, Kwang-Mo;Yoo, Hyung-Jun;Seo, Young-Seok;Park, Chan-Il;Kim, Il-Han;Ye, Seong-Jun;Park, Jae-Hong;Kim, Kum-Bae
    • Radiation Oncology Journal
    • /
    • v.25 no.4
    • /
    • pp.268-277
    • /
    • 2007
  • Purpose: Respiratory motion is a considerable inhibiting factor for precise treatment with stereotactic radiosurgery using the CyberKnife (CK). In this study, we developed a moving phantom to simulate three-dimensional breathing movement and investigated the distortion of dose profiles between the use of a moving phantom and a static phantom. Materials and Methods: The phantom consisted of four pieces of polyethylene; two sheets of Gafchromic film were inserted for dosimetry. Treatment was planned to deliver 30 Gy to virtual tumors of 20, 30, 40, and 50 mm diameters using 104 beams and a single center mode. A specially designed robot produced three-dimensional motion in the right-left, anterior-posterior, and craniocaudal directions of 5, 10 and 20 mm, respectively. Using the optical density of the films as a function of dose, the dose profiles of both static and moving phantoms were measured. Results: The prescribed isodose to cover the virtual tumors on the static phantom were 80% for 20 mm, 84% for 30 mm, 83% for 40 mm and 80% for 50 mm tumors. However, to compensate for the respiratory motion, the minimum isodose levels to cover the moving target were 70% for the $30{\sim}50$ mm diameter tumors and 60% for a 20 mm tumor. For the 20 mm tumor, the gaps between the isodose curves for the static and moving phantoms were 3.2, 3.3, 3.5 and 1.1 mm for the cranial, caudal, right, and left direction, respectively. In the case of the 30 mm tumor, the gaps were 3.9, 4.2, 2.8, 0 mm, respectively. In the case of the 40 mm tumor, the gaps were 4.0, 4.8, 1.1, and 0 mm, respectively. In the case of the 50 mm diameter tumor, the gaps were 3.9, 3.9, 0 and 0 mm, respectively. Conclusion: For a tumor of a 20 mm diameter, the 80% isodose curve can be planned to cover the tumor; a 60% isodose curve will have to be chosen due to the tumor motion. The gap between these 80% and 60% curves is 5 mm. In tumors with diameters of 30, 40 and 50 mm, the whole tumor will be covered if an isodose curve of about 70% is selected, equivalent of placing a respiratory margin of below 5 mm. It was confirmed that during CK treatment for a moving tumor, the range of distortion produced by motion was less than the range of motion itself.

Ichthyotoxic Cochlodinium polykrikoides red tides offshore in the South Sea, Korea in 2014: I. Temporal variations in three-dimensional distributions of red-tide organisms and environmental factors

  • Jeong, Hae Jin;Lim, An Suk;Lee, Kitack;Lee, Moo Joon;Seong, Kyeong Ah;Kang, Nam Seon;Jang, Se Hyeon;Lee, Kyung Ha;Lee, Sung Yeon;Kim, Mi Ok;Kim, Ji Hye;Kwon, Ji Eun;Kang, Hee Chang;Kim, Jae Seong;Yih, Wonho;Shin, Kyoungsoon;Jang, Poong Kook;Ryu, Joo-Hyung;Kim, Sung Young;Park, Jae Yeon;Kim, Kwang Young
    • ALGAE
    • /
    • v.32 no.2
    • /
    • pp.101-130
    • /
    • 2017
  • The ichthyotoxic Cochlodinium polykrikoides red tides have caused great economic losses in the aquaculture industry in the waters of Korea and other countries. Predicting outbreak of C. polykrikoides red tides 1-2 weeks in advance is a critical step in minimizing losses. In the South Sea of Korea, large C. polykrikoides red tide patches have often been recorded offshore and transported to nearshore waters. To explore the processes of offshore C. polykrikoides red tides, temporal variations in 3-dimensional (3-D) distributions of red tide organisms and environmental parameters were investigated by analyzing 4,432 water samples collected from 2-5 depths of 60 stations in the South Sea, Korea 16 times from May to Nov, 2014. In the study area, the vegetative cells of C. polykrikoides were found as early as May 7, but C. polykrikoides red tide patches were observed from Aug 21 until Oct 9. Cochlodinium red tides occurred in both inner and outer stations. Prior to the occurrence of large C. polykrikoides red tides, the phototrophic dinoflagellates Prorocentrum donghaiense (Jun 12 to Jul 11), Ceratium furca (Jul 11 to Aug 21), and Alexandrium fraterculus (Aug 21) formed red tides in sequence, and diatom red tides formed 2-3 times without a certain distinct pattern. The temperature for the optimal growth of these four red tide dinoflagellates is known to be similar. Thus, the sequence of the maximum growth rates of P. donghaiense > C. furca > A. fraterculus > C. polykrikoides may be partially responsible for this sequence of red tides in the inner stations following high nutrients input in the surface waters because of heavy rains. Furthermore, Cochlodinium red tides formed and persisted at the outer stations when $NO_3$ concentrations of the surface waters were < $2{\mu}M$ and thermocline depths were >20 m with the retreat of deep cold waters, and the abundance of the competing red-tide species was relatively low. The sequence of the maximum swimming speeds and thus potential reachable depths of C. polykrikoides > A. fraterculus > C. furca > P. donghaiense may be responsible for the large C. polykrikoides red tides after the small blooms of the other dinoflagellates. Thus, C. polykrikoides is likely to outgrow over the competitors at the outer stations by descending to depths >20 m and taking nutrients up from deep cold waters. Thus, to predict the process of Cochlodinium red tides in the study area, temporal variations in 3-D distributions of red tide organisms and environmental parameters showing major nutrient sources, formation and depth of thermoclines, intrusion and retreat of deep cold waters, and the abundance of competing red tide species should be well understood.

Numerical Simulation of Residual Currents and tow Salinity Dispersions by Changjiang Discharge in the Yellow Sea and the East China Sea (황해 및 동중국해에서 양쯔강의 담수유입량 변동에 따른 잔차류 및 저염분 확산 수치모의)

  • Lee, Dae-In;Kim, Jong-Kyu
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.10 no.2
    • /
    • pp.67-85
    • /
    • 2007
  • A three-dimensional hydrodynamic model with the fine grid is applied to simulate the barotropic tides, tidal currents, residual currents and salinity dispersions in the Yellow Sea and the East China Sea. Data inputs include seasonal hydrography, mean wind and river input, and oceanic tides. Computed tidal distributions of four major tides($M_2,\;S_2,\;K_1$ and $O_1$) are presented and results are in good agreement with the observations in the domain. The model reproduces well the tidal charts. The tidal residual current is relatively strong around west coast of Korea including the Cheju Island and southern coast of China. The current by $M_2$ has a maximum speed of 10 cm/s in the vicinity of Cheju Island with a anti-clockwise circulation in the Yellow Sea. General tendency of the current, however, is to flow eastward in the South Sea. Surface residual current simulated with $M_2$ and with $M_2+S_2+K_1+O_1$ tidal forcing shows slightly different patterns in the East China Sea. The model shows that the southerly wind reduces the southward current created by freshwater discharge. In summer during high runoff(mean discharge about $50,000\;m^3/s$ of Yangtze), low salinity plume-like structure(with S < 30.0 psu) extending some 160 km toward the northeast and Changjiang Diluted Water(CDW), below salinity 26 psu, was found within about 95 km. The offshore dispersion of the Changjiang outflow water is enhanced by the prevailing southerly wind. It is estimated that the inertia of the river discharge cannot exclusively reach the around sea of Cheju Island. It is noted that spatial and temporal distribution of salinity and the other materials are controlled by mixture of Changjiang discharge, prevailing wind, advection by flowing warm current and tidal current.

  • PDF