• Title/Summary/Keyword: 0-simple

Search Result 5,490, Processing Time 0.028 seconds

Mechanical properties of high strength lightweight self-compacting concrete using simple mixed design (간편배합설계 방법을 이용한 고강도경량 자기충전콘크리트의 역학적 특성)

  • Choi, Yun-Wang;Shin, Hwa-Cheol;Kim, Yong-Jic;Choi, Wook;Cho, Sun-Kyu
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.05a
    • /
    • pp.204-207
    • /
    • 2004
  • In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

  • PDF

Coronary Artery Numerical Flow Analysis for Determination of Bypass Graft Geometric Parameters

  • Kim, Hyung-Min;Kim, Woong
    • Journal of Mechanical Science and Technology
    • /
    • v.19 no.3
    • /
    • pp.905-912
    • /
    • 2005
  • A computational investigation of blood flow in a coronary artery grafted by artificial bypass was performed to determine such geometric parameters as the curvature of radius, approach length, and angle of end-to-side anastomosis. Transient flow features in the host artery were computed using FVM and SIMPLE algorithms. We compared flow distributions and wall shear stresses in two simple models, planar and non-planar, and confirmed that the non-planar bypass model was more conducive to suppressing intimal hyperplasia. Our non-planar model with $60^{\circ}$ of anastomosis and a 1.0 diameter approach length and radius of curvature predicts a relatively small, spatially-extended high-OSI (>0.01) zone, as well as an increased average wall shear stress on this zone.

A Simple Algorithm for Fast Codebook Search in Image Vector Quantization (벡터 양자화에서 벡터의 특성을 이용한 단축 탐색방법)

  • Koh, Jong-Seog;Kim, Jae-Kyoon;Kim, Seong-Dae
    • Proceedings of the KIEE Conference
    • /
    • 1987.07b
    • /
    • pp.1434-1437
    • /
    • 1987
  • We present a very simple algorithm for reducing the encoding (codebook search) complexity of vector quantization (VQ), exploiting some features of a vector currently being encoded. A proposed VQ of 16 (=$4{\times}4$) vector dimension and 256 codewords shows a slight performance degradation of about 0.1-0.9 dB, however, with only 16 or 32 among 256 codeword searches, i.e., with just 1/16 or 1/8 search complexity compared to a full-search VQ. And the proposed VQ scheme is also compared to and shown to be a bit superior to tree-search VQ with regard to their SNR performance and memory requirement.

  • PDF

Study on the Statistical Optimum Model of Simple Linear Regression to Estimate the Purchasing Price of Diamond (다이아몬드 구매가격 예측을 위한 통계적 단순 선형회기 최적화 모형에 관한 연구)

  • 이영욱
    • The Journal of Information Technology
    • /
    • v.3 no.1
    • /
    • pp.37-44
    • /
    • 2000
  • The purchasing estimate price of diamond is affected by the factors of carat, color, clarity, certificate, cut and price with the unit of $/carat. The object of this study is to obtain the linear regression model for such purchasing estimate price and to test statistically. The optimum model is the simple regression model of $^y{\;}:{\;}10^2{\;}/{\;}(-1.5575{\;}+{\;}0.3099{\;}logx){\;}+{\;}{\varepsilon}$ statistically satisfied by the lack of fit test and has the characteristics of normality, constant variance and symmetry.

  • PDF

Fabrication and Characterization of Solar Cells Using Cast Polycrystalline Silicon (Cast Poly-Si을 이용한 태양전지 제작 및 특성)

  • 구경완;소원욱;문상진;김희영;홍봉식
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.29A no.2
    • /
    • pp.55-62
    • /
    • 1992
  • Polycrystalline silicon ingots were manufactured using the casting method for polycrystalline silicon solar cells. These ingots were cut into wafers and ten n$^{+}$p type solar cells were made through the following simple process` surface etching, n$^{+}$p junction formation, metalization and annealing. For the grain boundary passivation, the samples were oxidized in O$_2$ for 5 min. at 80$0^{\circ}C$ prior to diffusion in Ar for 100 min. at 95$0^{\circ}C$. The conversion efficiency of polycrystalline silicon solar cells made from these wafers showed about 70-80% of those of the single crystalline silicon solar cell and superior conversion efficiency, compared to those of commercial polycrystalline wafers of Wacker Chemie. The maximum conversion efficiency of our wafers was indicated about 8%(without AR coating) in spite of such a simple fabrication method.

  • PDF

Mean Lifetime Estimation with Censored Observations

  • Kim, Jin-Heum;Kim, Jee-Hoon
    • Journal of the Korean Statistical Society
    • /
    • v.26 no.3
    • /
    • pp.299-308
    • /
    • 1997
  • In the simple linear regression model Y = .alpha.$_{0}$ + .beta.$_{0}$Z + .epsilon. under the right censorship of the response variables, the estimation of the mean lifetime E(Y) is an interesting problem. In this paper we propose a method of estimating E(Y) based on the observations modified by the arguments of Buckley and James (1979). It is shown that the proposed estimator is consistent and our proposed procedure in the simple linear regression case can be naturally extended to the multiple linear regression. Finally, we perform simulation studies to compare the proposed estimator with the estimator introduced by Gill (1983).83).

  • PDF

Simple Design of Equiripple Square Root Pulse Shaping Filter (자승근형 등리플 파형성형 필터의 간단한 설계)

  • 오우진
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.40 no.2
    • /
    • pp.64-69
    • /
    • 2003
  • In this paper, I introduce a simple design method using existing filter design method, such as Parks-McClecllan algorithm, for root-squared type raised cosine filter with equiripple characteristics, Thought some design examples, we show that the proposed filter has much better performance in ripple than the conventional SRCF at the expense of small increasing of ISI. In addition, the proposed filter is compatible with conventional SRCF. Finally, the filter for W-CDMA which uses RRC (Root Raised Cosine) with a=0.22 is designed in 12bit finite precision.

The Electrical and Optical Characteristics of Silica Sand by Terahertz Electromagnetic Pulses (테라헤르츠 전자기 펄스를 이용한 이산화규소의 전기적 광학적 특성)

  • 전태인
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.3
    • /
    • pp.202-206
    • /
    • 2001
  • Using THz time-domain spectroscopy (THz-TDS), the power absorption, the index of refraction, and the real conductivity of silica sand are measured from 0.1[Thz] to 0.5[Thz] frequency range. It is impossible to measure the characterization of the silica sand by simple electrical measurements using mechanical contacts, e.g., Hall effect or four-point probe measurements. However, the THz-TDS technique can measure not only electrical but also optical characterization of he sample. Also this technique can measure frequency dependent results. Especially, the real conductivity was increased according to THz frequency. This is unusual material compare with metal and semiconductor materials; the measured real conductivity are not followed by the simple Drude theory.

  • PDF

α -Cyclodextrin Modified Screen Printed Graphite Electrodes for Detection of Phenols

  • Kim, Hwa-jeong;Jang, Seung-Cheol;Shim, Yoon-Bo
    • Bulletin of the Korean Chemical Society
    • /
    • v.23 no.3
    • /
    • pp.427-431
    • /
    • 2002
  • A screen printed graphite electrode has been developed for a simple and sensitive determination of phenolic compounds in an aqueous solution. The electrode developed uses a simple and effective screen printing technique with ${\alpha}-Cyclodextrin({\alpha}-CD)$ modified graphite ink. Phenols were captured on the surface of the ${\alpha}-CD$ modified electrode through complex formation. The phenol/ ${\alpha}-CD$ complex was deposited and quantified electrochemically using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The optimization of the experimental parameters was performed in regard to electrode composition, pH, temperature, sample preconcentration time. Interferences from other organic compounds were investigated. The detection limit for phenols was 500 ${\pm}7$ nM for DPV, with the linear range of 0.5 ${\mu}M$ -25.0 ${\mu}M$ and 30 ${\pm}2$ nM for SWV, with the linear range of 30 nM - $50{\mu}M$, respectively.

A Convenient HPLC/ELSD Method for the Quantitative Analysis of Betaine in Lycium chinense

  • Lee, Sang-Myung;Park, Chae-Kyu;Cho, Byung-Goo;Cho, Kyoung-Shim;Min, Byung-Sun;Bae, Ki-Hwan
    • Natural Product Sciences
    • /
    • v.17 no.2
    • /
    • pp.104-107
    • /
    • 2011
  • In order to facilitate the quality control of betaine from the fruits of Lycium chinense, we have developed a rapid and simple method for quantitative determination. Determination was achieved on a Discovery C18 column with an isocratic solvent system of 0.32% perfluoropentanoic acid aqueous-acetonitrile at a flow-rate of 0.5 mL/min and detected an ELSD. The method was reproducible with intra- and inter-day variations of less than 6% (R.S.D). The recoveries were in the range of 90.01~100.05%. The method turned out to be fast and simple, furthermore, to have a good selectivity and sensitivity for the quantity determination of betaine in the fruits of L.chinense.