• Title/Summary/Keyword: Quarter

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Construction and Calibration Test of a Transmission-type Circular Polariscope for Photoelastic Stress Measurement (광탄성 응력측정을 위한 투과형 원형편광기 제작 및 시험)

  • Baek, T.H.;Koh, S.K.;Na, E.G.;Kim, J.S.;Cha, B.S.;Cho, C.H.
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.437-441
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    • 2001
  • This paper describes the construction of a circular polariscope. Generally, a circular polariscope contains four optical elements and a light source. The first element following the light source is called the polarizer. It converts the ordinary light into plane-polarized light. The second element is a quarter wave plate which converts the plane-polarized light into circularly polarized light. Following the quarter wave plate, a specimen made of transparent photoelastic material is located in a loading device. The second quarter wave plate is set and the last element is the analyzer. These polarizing elements, two quarter wave plates and two polarizing filters, were purchased from the USA. Frames and other structures for holding polarizing filters were machined and assembled to be rotated. Light box, which include four incandescent lamps and two sodium-vapor lamps, was made. In order to proof the function of the newly built polariscope, Tardy compensation test was applied to a rectangular shaped specimen made of poly-carbonate material (PSM1). The error of the fringe constant, which was measured by the newly built polariscope, was within 4.4 percent compared to the standard value of this material. It is possible to make a good quality of polariscope if accurate polarizing filters will be used.

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On Generalized 𝜙-recurrent Kenmotsu Manifolds with respect to Quarter-symmetric Metric Connection

  • Hui, Shyamal Kumar;Lemence, Richard Santiago
    • Kyungpook Mathematical Journal
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    • v.58 no.2
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    • pp.347-359
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    • 2018
  • A Kenmotsu manifold $M^n({\phi},\;{\xi},\;{\eta},\;g)$, (n = 2m + 1 > 3) is called a generalized ${\phi}-recurrent$ if its curvature tensor R satisfies $${\phi}^2(({\nabla}_wR)(X,Y)Z)=A(W)R(X,Y)Z+B(W)G(X,Y)Z$$ for all $X,\;Y,\;Z,\;W{\in}{\chi}(M)$, where ${\nabla}$ denotes the operator of covariant differentiation with respect to the metric g, i.e. ${\nabla}$ is the Riemannian connection, A, B are non-vanishing 1-forms and G is given by G(X, Y)Z = g(Y, Z)X - g(X, Z)Y. In particular, if A = 0 = B then the manifold is called a ${\phi}-symmetric$. Now, a Kenmotsu manifold $M^n({\phi},\;{\xi},\;{\eta},\;g)$, (n = 2m + 1 > 3) is said to be generalized ${\phi}-Ricci$ recurrent if it satisfies $${\phi}^2(({\nabla}_wQ)(Y))=A(X)QY+B(X)Y$$ for any vector field $X,\;Y{\in}{\chi}(M)$, where Q is the Ricci operator, i.e., g(QX, Y) = S(X, Y) for all X, Y. In this paper, we study generalized ${\phi}-recurrent$ and generalized ${\phi}-Ricci$ recurrent Kenmotsu manifolds with respect to quarter-symmetric metric connection and obtain a necessary and sufficient condition of a generalized ${\phi}-recurrent$ Kenmotsu manifold with respect to quarter symmetric metric connection to be generalized Ricci recurrent Kenmotsu manifold with respect to quarter symmetric metric connection.

Successful Treatment of Quarter Crack Using Wiring and Polymethylmethacrylate Composites in a Thoroughbred Racehorse (경주마에서 와이어와 폴리메틸메타크릴레이트 합성충진제를 사용한 제측열제의 치료 1례)

  • Park, Kyung-won;Ahn, Seoung-jue;Lee, Eun-bee;Chun, Yong-woo;Jeong, Hyohoon;Kang, Tae-Young;Seo, Jong-pil
    • Journal of Veterinary Clinics
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    • v.37 no.5
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    • pp.278-281
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    • 2020
  • A 4-year-old Thoroughbred stallion was referred to J&C Equine Hospital with a quarter crack of the right front foot. On visual inspection, there was a medial quarter crack with laminar necrosis. The first step to treat this problem was to remove the necrotized tissue around the crack using Dremel tools, disinfecting crack, administering antibiotics through regional limb perfusion and systemically administering antibiotics and anti-inflammatory drugs consistently. After one month's anti-inflammatory management, the quarter crack was treated successfully using two series of wiring with one week's term and polymethylmethacrylate composites (Equilox). After treatment, this racehorse successfully resumed training and racing in Korea Racing Authority Seoul Race Course, and won three times, finishing second and third place once, out of thirteen starts.

Analysis about relation of Long-term & Short-term Financial Market, Stock Market and Foreign Exchange Market of Korea (한국 장단기 금융시장, 주식 및 외환시장 연관성)

  • 김종권
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.50
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    • pp.105-125
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    • 1999
  • The results of analysis on foreign exchange market, stock and financial market after January of 1997 are that foreign exchange market will be affected by stock and financial market volatility about 1999. This means that stock and financial market are more stable than foreign exchange market. This also is supported by ‘financial market forecast of 1999 in Daewoo Economic Research Institute’. After won/dollar (end of period) will be increasing in 1,430 at second quarter of 1999, this is to downward 1,200 fourth quarter of 1999. This is somewhat based on government's higher exchange rate policy. But, after yield of corporate bond is to 11.0% at first quarter of 1999, this will be stable to 10.2% at fourth quarter. During the first quarter of 1999, yield of corporate bond is to somewhat increasing through sovereign debt and public bonds, technical adjustment of interest rate. After this, yield of corporate bond will be stable according to stability of price, magnification of money supply, restucturing of firms. So, stock market is favorably affected by stability of financial market. But, the pension and fund of USA, i.e., long-term portfolio investment fund, are injected through international firm's management. It is included by openness of audit, fair market about foreign investors. Finally, Moody's strong rating on the won-denominated bonds suggest that Korea's sovereign debt ratings could be restored to an investment grade in the near future. It sequentially includes inflow of foreign portfolio investment fund, fall of won/dollar foreign exchange rate (appreciation of won) and stability of yield of corporate bond.

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Sub-pixel Motion Estimation Algorithm with Low Computation Complexity for H.264 Video Compression (H.264 동영상 압축을 위한 낮은 복잡도를 갖는 부 화소 단위에서의 움직임 추정)

  • Lee, Yun-Hwa;Shin, Hyun-Chul
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.639-642
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    • 2005
  • Motion Estimation(ME) is an important part of video compression, because it requires a large amount of computation. Half-pixel and quarter-pixel motion estimation allows high video compression rates but it also has high computation complexity. In this paper we suggest a new and efficient motion estimation algorithm for half-pixel and quarter-pixel motion estimation using SAD values. In the method, an integer-pixel motion vector is found and then only three neighboring points of the integer-pixel motion vector is evaluated to find the half-pixel motion vector. The quarter-pixel motion vector is also found by using a similar method. Experimental results of our method shows 20% reduction in computation time, when compared with those of a conventional method, while producing same quality motion vectors.

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A Quarter-Wavelength Open Circuited Microstripline Slot Array ($\lambda$g/4 개방 마이크로스트립 선로 스로트의 배열)

  • 배정이
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.19 no.6
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    • pp.80-83
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    • 1982
  • A quarter-wavelength open circuited microstripline slot array is realized at X-band froquency. The optimal feeding point is experimentally determined. The input impedance of the slot array for various frequencies and its radiation pattern are measured. The bandwidth of the slot array is increased by using the 4$\times$4 elements which are slightly different in length and feeding network which is suggested in this papers.

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1/4 Car Vibration Simulation Using An Empirical MR Damper Model (실험적 MR댐퍼 모델을 사용한 1/4차량 진동 시뮬레이션)

  • Baek, Woon-Kyung;Yang, Bo-Suk;Lee, Jong-Seok;Kang, Tae-Ho;Ryu, Sung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.638-643
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    • 2005
  • This study is about a semi-active quarter car simulation method including a MR(magneto-rheological) damper. The MR damper was modeled as Spencer model that can capture nonlinear and hysteretic behavior. The parameters of the Spencer model were extracted from a random excitation test and optimum treatment of the test data. Then, a suspension control algorithm based on Sky-hook theory was applied for the quarter car simulation. Also, an experiment was dong using a quarter car simulator to confirm the simulation results with the Spencer MR damper model

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Dosimetric characteristics of an independent collimator system using measurements performed quarter fields. (Independent jaw를 이용한 비대칭조사면의 선량분포에 관한 연구)

  • Kim Geon O;Jeong Se Yeong;Kim Yeong Beom;Gwon Yeong Ho
    • The Journal of Korean Society for Radiation Therapy
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    • v.14 no.1
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    • pp.109-116
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    • 2002
  • The mordem linear accelerators are equipped with X-ray collimators that can be moved independently to allow asymmetric fields with field centers positioned away from the true central axis of the beam. We have studied the dosimetric of an independent collimator system using measurements performed quarter fields. The field size factors for asymmetric fields are compared to those for symmetric fields. Dosimetric measurements include portent depth don, beam penumbra and shape of isodose curves for symmetric and quarter fields.

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ON ALMOST r-PARACONTACT RIEMANNIAN MANIFOLD WITH A CERTAIN CONNECTION

  • Ahmad, Mobin;Haseeb, Abdul;Jun, Jae-Bok;Rahman, Shamsur
    • Communications of the Korean Mathematical Society
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    • v.25 no.2
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    • pp.235-243
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    • 2010
  • In a Riemannian manifold, the existence of a new connection is proved. In particular cases, this connection reduces to several symmetric, semi-symmetric and quarter symmetric connections, even some of them are not introduced so far. So, in this paper, we define a quarter symmetric semi-metric connection in an almost r-paracontact Riemannian manifold and consider invariant, non-invariant and anti-invariant hypersurfaces of an almost r-paracontact Riemannian manifold with that connection.

Design of MLC chip quadrature hybrid for 2 GHz band mobile communications (2 GHz대 이동 통신용 MLC 칩 90$^{\circ}$ 하이브리드 설계)

  • 심성훈;강종윤;윤석진;신현용;윤영중;김현재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.115-118
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    • 2002
  • This paper presents the design method and performance characteristics of a chip-type quadrature hybrid using LTCC-MLC technology. The design method for a chip-type quadrature hybrid is based on lumped element equivalent circuit of quarter-wave transformer. The chip-type quadrature hybrid was miniaturized to a greater extent using multilayer structure and lumped element. The proposed design method can also reduce the undesirable parasitic effects of the chip-type quadrature hybrid. The proposed chip-type quadrature hybrid was designed and fabricated using the proposed design method and the equivalent circuit model of a quarter-wave transformer. Fabrication and measurement of designed chip-type quadrature hybrid show much smaller size than a conventional distributed quadrature hybrid and a good agreement with simulated results.

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