• Title/Summary/Keyword: 내면파

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Wave Analysis of Forced In-Plane Vibration of Plates (탄성파를 이용한 평판의 강제 내면전동 해석)

  • Kil Hyun-Gwon;Choi Jae-Sung;Hong Suk-Yoon
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.297-302
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    • 1999
  • 평판의 일반적인 형태의 진동을 해석하기 위해서는, 외면진동뿐만이 아니라 내면진동을 해석하여야 한다. 평판 내면진동의 경우 탄성파인 종파와 전단파의 전파에 의한 영향으로 발생하며, 진동 변위, 진동 에너지, 진동 인텐시티 등의 특성들을 이해하기 위해서는 각 파동의 영향을 분리하여 낼 필요가 있다. 내면진동을 해석하기 위하여 진동 모드법을 사용할 수 있으나, 각 파동에 의한 영향을 분리하여 낼 수가 없다. 본 논문에서는 진동장을 탄성파들에 의한 영향의 합으로 나타냄으로써, 각 파동에 의한 진동 변위, 진동 에너지, 진동 인텐시티 둥의 영향들을 분리할 수 있는 해석 방법을 제안하고자 한다. 이러한 해석 방법을 이용하여 점가진력에 의하여 강제 진동하는 평판의 내면 진동장에 대한 수치 계산을 수행하였다. 결과로써 진동 변위, 진동 에너지, 진동 인텐시티 등을 이루는 탄성파들의 기여도와 특성들을 분석함으로써 본 해석기법의 유용성을 보였다.

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Numerical Computations on the Hydrodynamic Forces by Internal Waves in a Sediment Pocket (퇴적 침전구에서 발생하는 내면파 유동에 의한 유체력 해석)

  • Kyoung Jo-Hyun;Kim Jang-Whan;Bai Kwang-June
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.7 no.4
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    • pp.192-198
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    • 2004
  • A numerical method is developed to solve a two-dimensional diffraction problem for a body located in a sediment pocket where a heavier muddy water is trapped. In the present study, the wave exciting forces acting on a submerged body in the water-sediment interface by an incident wave is investigate. It is assumed that the heavier mud is trapped locally in a sediment pocket. A mathematical formulation is made in the scope of the potential theory. The fluid is assumed to be inviscid, incompressible and its motion irrotational. The boundary conditions on the unknown free surface and interface are linearized. As a method of solution, the localized finite-element method is adopted. In the method, the computation domain is reduced by utilizing the complete set of analytic solutions known in the infinite subdomain to be truncated by introduction of an appropriate juncture conditions. The main advantage of this method is that any complex geometry of the boundaries can be easily accommodated. Computations are carried out for mono-chromatic plane progressive surface waves normally incident on the domain. Numerical results are compared with those obtained by Lassiter based on Schwingers variational method. Good Agreements are obtained in general. Another numerical computations are made for the cases with and without a body in the sediment pocket.

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Internal Wave Computations based on a Discontinuity in Dynamic Pressure (동압 계수의 불연속성을 이용한 내면파의 수치해석)

  • 신상묵;김동훈
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.4
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    • pp.17-29
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    • 2004
  • Internal waves are computed using a ghost fluid method on an unstructured grid. Discontinuities in density and dynamic pressure are captured in one cell without smearing or oscillations along a multimaterial interface. A time-accurate incompressible Navier-Stokes/Euler solver is developed based on a three-point backward difference formula for the physical time marching. Artificial compressibility is introduced with respect to pseudotime and an implicit method is used for the pseudotime iteration. To track evolution of an interface, a level set function is coupled with the governing equations. Roe's flux difference splitting method is used to calculate numerical fluxes of the coupled equations. To get higher order accuracy, dependent variables are reconstructed based on gradients which are calculated using Gauss theorem. For each edge crossing an interface, dynamic pressure is assigned for a ghost node to enforce the continuity of total pressure along the interface. Solitary internal waves are computed and the results are compared with other computational and experimental results.

Experimental Study on the Suppression of low Frequency Unstable Burning Occurred in a Gas Generator Using Bundle Cylindrical Grain (다발 원통형 그레인을 사용한 가스발생기의 저주파 연소불안정 소멸에 대한 실험적 연구)

  • Sung Hong-Gye;Byun Jong-Ryul
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.3
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    • pp.10-16
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    • 2004
  • Untypical unstable burning with very low frequency was observed at firing test of a gas generator using bundle cylindrical grain. The pressure unbalance between inside and outside of cylindrical grain brought such a low unstable burning. The grains were radially holed so that the high pressure gas inside of grain could quickly moved outward of gain, resulting dissipation of the pressure unbalance However too many holes were required to let the burning be stable for all operation regime from low to high temperature of grain and resultantly deteriorate the Progressive increase of gas amount produced by a gas generator. So another idea using grids located both sides of a bundle grain was applied to dissipate actively large vorticities enhanced by unbalance pressure distribution in a combustor. Finally stable burning with progressively increase of gas was established by application of 5${\times}$5 grid slightly away bundle grain to move bundle gain freely in case pressure unbalance were occurred inside of combustor.

NUMERICAL SIMULATION OF THREE-DIMENSIONAL INTERNAL WAVES USING THE FDS SCHEME ON THE HCIB METHOD (FDS 기법과 HCIB법을 이용한 3차원 내면파 수치 모사)

  • Shin, Sang-Mook
    • Journal of computational fluids engineering
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    • v.17 no.1
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    • pp.8-15
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    • 2012
  • A code developed using the flux-difference splitting scheme on the hybrid Cartesian/immersed boundary method is applied to simulate three-dimensional internal waves. The material interface is regarded as a moving contact discontinuity and is captured on the basis of mass conservation without any additional treatment across the interface. Inviscid fluxes are estimated using the flux-difference splitting scheme for incompressible fluids of different density. The hybrid Cartesian/immersed boundary method is used to enforce the boundary condition for a moving three-dimensional body. Immersed boundary nodes are identified within an instantaneous fluid domain on the basis of edges crossing a boundary. The dependent variables are reconstructed at the immersed boundary nodes along local normal lines to provide the boundary condition for a discretized flow problem. The internal waves are simulated, which are generated by an pitching ellipsoid near an material interface. The effects of density ratio and location of the ellipsoid on internal waves are compared.

A Study of the Narrative Structure and the Writer's Intent in the Hasaenggiwoojun(何生奇遇傳) (<하생기우전>의 서사구조와 작가적 의미 - 갈등양상을 중심으로 -)

  • Moon, Beom-doo
    • Journal of Korean Classical Literature and Education
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    • no.37
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    • pp.111-149
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    • 2018
  • This story is written by Shin Kwang-han who is a famous scholar and writer in Josun Dynasty. The most notable feature of this story is the love between a man and a dead woman. The protagonist has failed the test to be a national official for several years, because of the corruption and unfairness of the leaders of his society. He is very upset, but then changes his mind in order to become an officer. One day he meets a dead woman. He saves her life from death, and falls in love with her. Finally he marries her and attains a high position. Till now, all the aspects of this story have been extensively researched from a number of different perspectives. However the narrative structure of this story has not been discussed much. This story belongs to Jungi-novel, a kind of old story style which includes fantasy. The studies on this story have mostly been carried out to find the different features in comparison with other works of the same style. Further, we could not understand its own specific meaning structure. This study aims to find the narrative structure of this story. It was recognized by researchers that Shin's stories talk about his life and his perspective of the world. Further, I will try to show how he expresses his thoughts, emotion and life through this story. First, to obtain a satisfactory result through this study, I will find a way to resolve several problems that have become the center of the controversy. Afterward, the conflict and resolution the hero's relation to the world will be identified in every paragraph. Through these efforts, we will have a new point of the view about the narrative structure of this story and the intent expressed by the writer through its structure.

Myth with the Times -Return of Pygmalion- (시대와 함께하는 신화 -피그말리온의 귀환-)

  • Kim, Mihye
    • The Journal of the Korea Contents Association
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    • v.13 no.10
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    • pp.140-150
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    • 2013
  • The Greek sculptor, Pygmalion, created a sculpture which was perfect in shape and fell in love with it. He prayed the goddess of love, Venus to transform it into a real woman. She answered his asking, and he finally got married to her. In Bernard Shaw's movie, , the linguist, Dr. Higgins, brought a street girl, Eliza Doolittle to his home and educated her standard London dialect and upper-class manners. Unlike the Greek sculptor, Higgins changed not only her appearance but also her inner identity, then she became 'a new woman' of the age. Abby in seems to live a successful life of thorough planning and pursuing knowledge, but there is no place for her to express natural instinct and human emotion. On the other hand, Mike is a totally different type of a person from her. Like a Greek sculptor, he changes her into a woman who can truly understand other people from her heart and listen to what her inner-self says to her. The Greek myth metaphorically suggests the way to build true relationships between people of all times.

Case study of Music & Imagery for Woman with Depression (우울한 내담자를 위한 MI(Music & Imagery) 치료사례)

  • Song, In Ryeong
    • Journal of Music and Human Behavior
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    • v.5 no.1
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    • pp.67-90
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    • 2008
  • This case used MI techniques that give an imagery experience to depressed client's mental resource, and that makes in to verbalism. Also those images are supportive level therapy examples that apply to positive variation. MI is simple word of 'Music and Imagery' with one of psychology cure called GIM(Guided Imagery and Music). It makes client can through to the inner world and search, confront, discern and solve with suitable music. Supportive Level MI is only used from safety level music. Introduction of private session can associate specification feeling, subject, word or image. And those images are guide to positive experience. The First session step of MI program is a prelude that makes concrete goal like first interview. The Second step is a transition that can concretely express about client's story. The third step is induction and music listening. And it helps to associate imagery more easily by used tension relaxation. Also it can search and associate about various imagery from the music. The last step is process that process drawing imagery, talking about personal imagery experience in common with therapist that bring the power by expansion the positive experience. Client A case targets rapport forming(empathy, understanding and support), searching positive recourse(child hood, family), client's emotion and positive support. Music must be used simple tone, repetition melody, steady rhythm and organized by harmony music of what therapist and client's preference. The client used defense mechanism and couldn't control emotion by depression in 1 & 2 sessions. But the result was client A could experience about support and understanding after 3 sessions. After session 4 the client had stable, changed to positive emotion from the negative emotion and found her spontaneous. Therefore, at the session 6, the client recognized that she will have step of positive time at the future. About client B, she established rapport forming(empathy, understanding and support) and searching issues and positive recognition(child hood, family), expression and insight(present, future). The music was comfortable, organizational at the session 1 & 2, but after session 3, its development was getting bigger and the main melody changed variation with high and low of tune. Also it used the classic and romantic music. The client avoids bad personal relations to religious relationship. But at the session 1 & 2, client had supportive experience and empathy because of her favorite, supportive music. After session 3, client B recognized and face to face the present issue. But she had avoidance and face to face of ambivalence. The client B had a experience about emotion change according depression and face to face client's issues After session 4. At the session 5 & 6, client tried to have will power of healthy life and fairly attitude, train mental power and solution attitude in the future. On this wise, MI program had actuality and clients' issues solution more than GIM program. MI can solute the issue by client's based issue without approach to unconsciousness like GIM. Especially it can use variety music and listening time is shorter than GIM and structuralize. Also can express client's emotion very well. So it can use corrective and complement MI program to children, adolescent and adult.

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The effect of cavity wall property on the shear bond strength test using iris method (Iris 법을 이용한 전단접착강도 측정에서 와동벽의 영향)

  • Kim, Dong-Hwan;Bae, Ji-Hyun;Cho, Byeong-Hoon;Lee, In-Bog;Baek, Seung-Ho;Ryu, Hyun-Mi;Son, Ho-Hyun;Um, Chung-Moon;Kwon, Hyuck-Choon
    • Restorative Dentistry and Endodontics
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    • v.29 no.2
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    • pp.170-176
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    • 2004
  • Objectives : In the unique metal iris method. the developing interfacial gap at the cavity floor resulting from the cavity wall property during polymerizing composite resin might affect the nominal shear bond strength values. The aim of this study is to evaluate that the iris method reduces the cohesive failure in the substrates and the cavity wall property effects on the shear bond strength tests using iris method. Materials and Methods : The occlusal dentin of 64 extracted human molars were randomly divided into 4 groups to simulate two different levels of cavity wall property (metal and dentin iris) and two different materials ($ONE-STEP^{\circledR}$ and $ALL-BOND^{\circledR}$ 2) for each wall property. After positioning the iris on the dentin surface. composite resin was packed and light-cured. After 24 hours the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Fracture analysis was performed using a microscope and SEM. The data was analyzed statistically by a two-way ANOV A and t-test. Results : The shear bond strength with metal iris was significant higher than those with dentin iris (p=0.034). Using $ONE-STEP^{\circledR}$, the shear bond strength with metal iris was significant higher than those with dentin iris (p=0.005), but not in $ALL-BOND^{\circledR}$ 2 (p=0.774). The incidence of cohesive failure was very lower than other shear bond strength tests that did not use iris method. Conclusions:The iris method may significantly reduce the cohesive failures in the substrates. According to the bonding agent systems. the shear bond strength was affected by the cavity wall property.

A Study on the Tasks for the Preparation Process and Application of Faith Education Related to Experience (경험과 관련된 신앙교육 수업 준비과정과 적용을 위한 과제 연구)

  • Han, Kyoung-mi
    • Journal of Christian Education in Korea
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    • v.70
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    • pp.207-238
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    • 2022
  • Faith education focuses on 'changing the direction of life' that pursues the life of Christ. This is possible only when the message of the Bible is embodied in life, not by accumulating biblical knowledge. Today, however, faith education does not allow biblical messages to be embodied in life. This is the result of focusing on knowing the Bible itself, instead of guiding the faith education to meet the Bible and the experience of human life. Church education emphasized the inner faith of individuals rather than changes in life and practice, preparing for the afterlife, and mostly for the training and quantitative growth of the church. As a result, in the COVID-19 era, Protestants showed an immature appearance that only cared about the safety of the church, and social trust in Protestants was lost. Therefore, faith education should educate what life of the Bible and the experiences of the learner will meet and respond to God in order for the Bible's message to be realized in life. I tried to find out how to prepare for this faith education in detail. So I would like to look at "The preparation process for religious classes related to experience" compiled by the German Protestant Lutheran Bavarian Presbyterian Church and present tasks for application to the Korean Church. Preparation for experience-related religious classes consists of five courses. It is a personal meeting, a theological orientation, a pedagogical orientation, a pedagogical decision, and a summary of the progress plan. The main purpose of this process is to learn how biblical believers interpreted their experiences in life from the perspective of faith and tried to overcome the problem. Faith education related to experience deals with the essence of faith education, not one of the Bible teaching methods. Although the field of education is in the social change of expanding from the real world to the virtual world, the essential nature of faith education cannot change. Therefore, research and application of faith education related to experience in Korean churches will help the biblical message to be embodied in Christian life.