• Title/Summary/Keyword: moment fields

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The Comparative Kinematic Analysis of a Volleyball Spike Serve (배구 스파이크 서브 동작의 운동학적 비교 분석)

  • Park, Jong-Chul;Back, Jin-Ho;Lee, Jin-Taek
    • Korean Journal of Applied Biomechanics
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    • v.19 no.4
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    • pp.671-680
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    • 2009
  • We performed a study to obtain kinematic data on the characteristics of spike serving techniques used by volleyball players, including other basic data that will be useful for in-field applications. We used three-dimensional videography to compare good tough serves and serve errors. The subjects were 3 left attackers whose spike serves were videographed (60 fileds/s). The three-dimensional coordinates were calculated using the direct linear transformation method and then analyzed using the Kwon 3D software program version 3.1. There was no difference in time elapsed. However, the vertical displacement of the center of body mass(CM) differed between the 2 types of serves: in successful serves, the CM tended to be lower, as did the maximum ball height at the time of hitting. Further, the higher the level of the hitting hand was at the moment of impact, the higher was the likelihood of scoring points. In good serves, the players tended to accelerate their CM movement just before jumping to hit the ball and descend rapidly at the moment of hitting. The hand speed along with ball velocity during the impact was proven to be higher in successful serves. Moreover, in successful serves, the shoulder angles increased to a greater extent while the elbow angles were maintained constant. This possibly resulted in faster and more precise serves. An important observation was that the angle of trunk inclination during the jump did not increase with the swing of the shoulders, muscle tendon complex.

Crystallographic and Magnetic Properties of $NdFe_{10.7}Ti_{1.3}$ ($NdFe_{10.7}Ti_{1.3}$의 결정학적 및 자기적 성질 연구)

  • 이승화;이용종;안성용;김철성;김윤배;김창석
    • Journal of the Korean Magnetics Society
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    • v.6 no.6
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    • pp.361-366
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    • 1996
  • $NdFe_{10.7}Ti_{1.3}$ has been studied with X-ray diffraction, Mossbauer spectroscopy and vibrating sample magnet-ometer(VSM). The alloys were prepared by arc-melting under an argon atmosphere. The $NdFe_{10.7}Ti_{1.3}$ contains some $\alpha-Fe$, from X-ray and Mossbauer measurements. The $NdFe_{10.7}Ti_{1.3}$ has the $ThMn_{12}$-type tetragonal struc-ture with $a_{0}=8.607{\AA}\;and\;c_{0}=4.790{\AA}$. The Curie temperature ($T_c$) of the $NdFe_{10.7}Ti_{1.3}$ is 590 K from $M\"{o}ssbauer$ spectroscopy performed at various temperatures ranging from 13 to 800 K. Each spectrum below $T_c$ was fitted with six subspectra of Fe sites in the structure$(8i_{1},\;8i_{2},\;8j_{2},\;8j_{1},\;8f\;and\;{\alpha}-Fe)$. The area fractions of the subspectra at room temperature are 13.8%, 15.4%, 17%, 16.4%, 34.1% and 3.3%, respectively. Magenetic hyperfine fields for the Fe sites decrease in the order, $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$. The abrupt changes in the magnetic hyperfine field, isomer shift and magnetic moment observed at about 180 K in $NdFe_{10.7}Ti_{1.3}$ are attributed to spin reorientation.

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Improvement of multi layer perceptron performance using combination of adaptive moments and improved harmony search for prediction of Daecheong Dam inflow (대청댐 유입량 예측을 위한 Adaptive Moments와 Improved Harmony Search의 결합을 이용한 다층퍼셉트론 성능향상)

  • Lee, Won Jin;Lee, Eui Hoon
    • Journal of Korea Water Resources Association
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    • v.56 no.1
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    • pp.63-74
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    • 2023
  • High-reliability prediction of dam inflow is necessary for efficient dam operation. Recently, studies were conducted to predict the inflow of dams using Multi Layer Perceptron (MLP). Existing studies used the Gradient Descent (GD)-based optimizer as the optimizer among MLP operators to find the optimal correlation between data. However, the GD-based optimizers have disadvantages in that the prediction performance is deteriorated due to the possibility of convergence to the local optimal value and the absence of storage space. This study improved the shortcomings of the GD-based optimizer by developing Adaptive moments combined with Improved Harmony Search (AdamIHS), which combines Adaptive moments among GD-based optimizers and Improved Harmony Search (IHS). In order to evaluate the learning and prediction performance of MLP using AdamIHS, Daecheong Dam inflow was learned and predicted and compared with the learning and prediction performance of MLP using GD-based optimizer. Comparing the learning results, the Mean Squared Error (MSE) of MLP, which is 5 hidden layers using AdamIHS, was the lowest at 11,577. Comparing the prediction results, the average MSE of MLP, which is one hidden layer using AdamIHS, was the lowest at 413,262. Using AdamIHS developed in this study, it will be possible to show improved prediction performance in various fields.

Post-Medium and Postproduction: Contemporaneity of Contemporary Art (포스트-미디엄과 포스트프로덕션 : 포스트모더니즘 이후 현대미술의 '동시대성(contemporaneity)')

  • Chung, Yeon Shim
    • The Journal of Art Theory & Practice
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    • no.14
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    • pp.187-215
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    • 2012
  • In recent studies of art historical methodology, such as Critical Terms for Art History and The Art of Art History, subjectivity, identity, abjection, and other terms have been placed safely in the genealogy of contemporary art history. This paper questions the contemporaneity in the story of contemporary art in our time in relation to two other critical terms that have been regularly cited by contemporary critics, not only in Euro-American fields but also in Korea. The terms are postmedium and postproduction, respectively, as used by Rosalind Krauss and Nicolas Bourriaud. This paper stems from the critical condition in which art criticism and theory have their power in the rise of neo-liberalism. But this paper does not deal with the contemporary as a chronological term for art history but rather examines the three critical terms-contemporaneity, post-medium, and postproduction-that have garnered scholarly attention. I would like to put aside postmodernism for the moment; I don't disregard the postmodern condition although the death of postmodern critical terms has resulted in the loss of its polemical power in art worlds such as in exhibitions, etc. To look at "the postproduction in the age of post-medium age after postmodernism," I first explore Krauss's notion of post-medium because, unlike media artists like Lev Manovich and Peter Weibel, Krauss's post-medium condition is different and insists on medium specificity. In this sense, Krauss has turned out to be another Greenberg in disguise. For her, photography and video are expanded mediums after Greenberg, because Krauss has spent her life explicating those mediums. Under the Cup, her recent publication, came out in 2011, and discusses her desire to defend medium-specificity against the intermedia of installation art found ubiquitously in international exhibitions and biennales. Her usage of post-medium has been taken up by Weibel as postmedia in a broader sense. But whether the post-medium condition or the postmedia age, we nonetheless enter the new age of the contemporary. Consequently, this paper questions what constitutes contemporaneity in our times. It is said that there is nothing new on earth, yet I find original artistic strategies among the younger generation in the postmedia age. The contemporary justifies its place in art fields and criticism by keeping its distance from postmodernism although we still find the remnants of postmodern artistic practices and theoretical foundations. By looking at materials written by Terry Smith, I would like to examine contemporaneity as a rhetoric where artists, critics, and curators endeavor to set up a new spirit of criticism, distant from the past of modernism and postmodernism. In discussions, modernism and postmodernism act as catalysts interacting with each other while justifying their own place. In conclusion, my paper reaches to delineate where the contemporary finds its place among artists' responses and working methods. It explores the postproduction of the Internet and the World Wide Web generations, where images become data rather than representation (of modernism) and appropriation (of postmodernism). This paper analyzes Bourriaud's text, as well as relevant artists like Pierre Huyghe, Liam Gillick, and others. By examining the aforementioned critical terms, I would like to reconsider our own contemporary art in Korea, especially among young artists influenced by digital media and the World Wide Web in the 1990s.

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The Analysis of Japanese Public Libraries' Characteristics by Types: Focused on the Consideration of Liaison Between Service Contents and Service Space (일본 공립도서관의 유형별 특성 분석 - 서비스내용과 서비스공간의 연계적 고찰을 중심으로 -)

  • Jung, A-Young
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.23 no.2
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    • pp.171-185
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    • 2012
  • This study takes note on the need for the consideration of the relationship between the service contents and service space which libraries provide, since at the moment the demands of library users, purpose of using it, etc. gradually become varied. In this study, type classification of public libraries was done focused on the relationship between service contents and service space, targeting Japanese public libraries. Through linking approach between service contents and service space, the analysis of Japanese public libraries' characteristics and type characteristics could be captured. This study has ultimately aimed to prepare for the basic data which will help Korean public libraries to make connection between service contents and service space in the future. The collected service contents and service space had been analyzed by multi-dimensional data analysis methods such as the "Quantification Theory Analysis Type III" and "Cluster Analysis". After characters of libraries were analyzed, the findings of this study show the views such as "the field of information provided, the method of information provision, and the object of service provision." And types of 44 libraries are classified into those which have 6 kinds of characteristics as follows : (1) group-oriented libraries which provide the jobs and employment information, (2) libraries which provide the jobs and employment information through the counselling space, (3) individual-oriented libraries which provide the information of education-related fields, (4) group-oriented libraries which provide the information of education-related fields, (5) libraries which provide information focusing on the counselling space, (6) individual-oriented libraries which focused on the service provision.

Crystallograpbic and Magnetic Properties of $Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$ ($Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$의 결정학적 및 자기적 특성 연구)

  • 김우철;김삼진;김철성;이승화
    • Journal of the Korean Magnetics Society
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    • v.9 no.3
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    • pp.136-142
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    • 1999
  • $Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$ has been studied with x-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometer. The crystal structure is found to be a cubic spinel with the lattice constant $a_0=8.403{\AA}$. Mossbauer spectra of have been taken at various temperatures ranging from 12 K to 665 K. as the temperature increases toward $T_N$ a systematic line broadening effect in the Mossbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magenetic hyperfine fields at various iron sites. Also, by using binomial distribution equation we obtained the hyperfine fields of tetrahedral[A] and octahedral sites[B], $H_{hf}(A)=470\;kOe,\; H_{hf}(B0)=495 \;kOe,\; H_{hf}(B1)=485\;kOe, \;H_{hf}(B2)=453\;kOe,\; H_{hf}(B3)=424\;kOe,\; H_{hf}(B4)=390\;kOe,\; H_{hf}(Bavr)=451\;kOe$ respectively at room temperature. The isomer shift indicates that the iron ions are ferric at tetrahedral[A] and octahedral sites[B], respectively. The Neel temperature is determined to be $T_N=665\;K$. The results of the VSM data gave the magnetic moment and coercivity values of $M_S=66\; emu/g\;and\;H_C=36\;Oe$.

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Crystallographic and Magnetic Properties of Nano-sized Nickel Substituted Cobalt Ferrites Synthesized by the Sol-gel Method

  • Choi, Won-Ok;Lee, Jae-Gwang;Kang, Byung-Sub;Chae, Kwang Pyo
    • Journal of Magnetics
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    • v.19 no.1
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    • pp.59-63
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    • 2014
  • Nano-sized nickel substituted cobalt ferrite powders, $Ni_xCo_{1-x}Fe_2O_4$ ($0.0{\leq}x{\leq}1.0$), were fabricated by the sol-gel method, and their crystallographic and magnetic properties were studied. All the ferrite powders showed a single spinel structure, and behaved ferrimagnetically. When the nickel substitution was increased, the lattice constants and the sizes of particles of the ferrite powders decreased. The M$\ddot{o}$ssbauer absorption spectra of $Ni_xCo_{1-x}Fe_2O_4$ ferrite powders could be fitted with two six-line subspectra, which were assigned to a tetrahedral A-site and octahedral B-sites of a typical spinel crystal structure. The increase in values of the magnetic hyperfine fields indicated that the superexchange interaction was stronger, with the increased nickel concentration in $Ni_xCo_{1-x}Fe_2O_4$. This could be explained using the cation distribution, which can be written as, $(Co_{0.28-0.28x}Fe_{0.72+0.28x})[Ni_xCo_{0.72-0.72x}Fe_{1.28-0.28x}]O_4$. The two values of the saturation magnetization and the coercivity decreased, as the rate of nickel substitution was increased. These decreases could be explained using the cation distribution, the magnetic moment, and the magneto crystalline anisotropy constant of the substituted ions.

Morphogenetic Alterations of Alternaria alternata Exposed to Dicarboximide Fungicide, Iprodione

  • Kim, Eunji;Lee, Hye Min;Kim, Young Ho
    • The Plant Pathology Journal
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    • v.33 no.1
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    • pp.95-100
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    • 2017
  • Fungicide-resistant Alternaria alternata impede the practical control of the Alternaria diseases in crop fields. This study aimed to investigate cytological fungicide resistance mechanisms of A. alternata against dicarboximide fungicide iprodione. A. alternata isolated from cactus brown spot was cultured on potato-dextrose agar (PDA) with or without iprodione, and the fungal cultures with different growth characteristics from no, initial and full growth were observed by light and electron microscopy. Mycelia began to grow from one day after incubation (DAI) and continued to be in full growth (control-growth, Con-G) on PDA without fungicide, while on PDA with iprodione, no fungal growth (iprodione-no growth, Ipr-N) occurred for the first 3 DAI, but once the initial growth (iprodione-initial growth, Ipr-I) began at 4-5 DAI, the colonies grew and expanded continuously to be in full growth (iprodione-growth, Ipr-G), suggesting Ipr-I may be a turning moment of the morphogenetic changes resisting fungicidal toxicity. Con-G formed multicellular conidia with cell walls and septa and intact dense cytoplasm. In Ipr-N, fungal sporulation was inhibited by forming mostly undeveloped unicellular conidia with degraded and necrotic cytoplasm. However, in Ipr-I, conspicuous cellular changes occurred during sporulation by forming multicellular conidia with double layered (thickened) cell walls and accumulation of proliferated lipid bodies in the conidial cytoplasm, which may inhibit the penetration of the fungicide into conidial cells, reducing fungicide-associated toxicity, and may be utilized as energy and nutritional sources, respectively, for the further fungal growth to form mature colonies as in Ipr-G that formed multicellular conidia with cell walls and intact cytoplasm with lipid bodies as in Con-G.

Optimal Conditions of Single Cell Gel Electrophoresis (Comet) Assay to detect DNA single strand breaks in Mouse Lymphoma L5178Y cells

  • Ryu, Jae-Chun;Kwon, Oh-Seung;Kim, Hyung-Tae
    • Environmental Mutagens and Carcinogens
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    • v.21 no.2
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    • pp.89-94
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    • 2001
  • Recently, single cell gel electrophoresis, also known as comet assay, is widely used for the detection and measurement of DNA strand breaks in vitro and in vivo in many toxicological fields such as radiation exposure, human monitoring and toxicity evaluation. As well defined, comet assay is a sensitive, rapid and visual method for the detection of DNA strand breaks in individual cells. Briefly, a small number of damaged cells suspended in a thin agarose gel on a microscope slide were lysed, unwinded, electrophoresed, and stained with a fluorescent DNA binding dye. The electric current pulled the charged DNA from the nucleus such that relaxed and broken DNA fragments migrated further. The resulting images which were subsequently named for their appearance as comets, were measured to determine the extent of DNA damages. However, some variations could be occurred in procedures, laboratories's conditions and kind of cells used. Hence, to overcome and to harmonize these matters in comet assay, International Workshop on Genotoxicity Test Procedure (IWGTP) was held with several topics including comet assay at Washington D.C. on March, 1999. In spite of some consensus in procedures and conditions in IWGTP, there are some problems still remained to be solved. In this respect, we attempted to set the practical optimal conditions in the experimental procedures such as lysis, unwinding, electrophoresis and neutralization conditions and so on. First of all, we determined optimal lysis and unwinding time by using 150 $\mu$M methyl methanesulfonate (MMS) which is usually used concentration. And then, we determined optimal positive control concentrations of benzo(a)pyrene (BaP) and MMS in the presence and absence of S9 metabolic activation system, respectively.

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A Research into Deconstructive Features in Visual Communication Design

  • Hong Dong-Sik
    • Archives of design research
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    • v.19 no.3 s.65
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    • pp.207-218
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    • 2006
  • 21st century is called digital and information era. The visual communication becomes more important than any other centuries. Visual communication design has been represented in varied images from ancient society up until the present time. Especially graphic design, which has experienced artistic upheaval from modernism and postmodernism, has been enabled to deliver messages in a more developed and sensuous appearances. Deconstructionist design wasn't well received by modernism, an advocate of practicality and effectiveness; however, as the beginning of subsequent postmodernism, it started to earn a warm welcome from a number of designers. Postmodernism made it possible for deconstruction to be a new paradigm appreciating neutral respect for varied expressions and designers' idiosyncrasy. Corresponding to this new trend, Edward Fella published his artwork 'Letters on America', which introduced a variety of vernacular design works in America. It was the result of years of research, and included materials which were not something completely new to field of communication design but rather symbolic, deconstructive images available everywhere around us. Deconstruction broke away from the previous modernism's unity and standards, and sought to achieve a new tensional deliverance. As a consequence, images were created in destructive and incomplete forms. Graphic design also complied with this new code and its advent fascinated the artists in the fields of advertising, editorial and poster designs. This paper contends that contemporary graphic design still maintains a deconstructive representation, examines its locality in design works from an aesthetic viewpoint, and researches theoretical approaches to deconstructionist and case studies conducted domestically. There has been incessant critical contradiction in terms of the heritage of deconstruction. I would like to present you with a moment in which you can struggle to decide whether it is a result of an effort to get away from modernism or an offspring of postmodernism.

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