• Title/Summary/Keyword: MC model

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Design and Characteristic Analysis of MC-LOA taking into account the Magnetic Circuit unequivalence (자기회로의 불평형을 고려한 MC-LOA의 설계 및 특성 해석)

  • Eum, Sang-Joon;Kim, Duk-Hyun;Kang, Gyu-Hong;Hong, Jung-Pyo;Kim, Gyu-Tak
    • Proceedings of the KIEE Conference
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    • 1999.07a
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    • pp.145-147
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    • 1999
  • A voice type Moving Coil Linear Oscillatory Actuator(MC-LOA) has unbalanced magnetic circuit structure. Its asymmetric magnetic flux distribution along the mover directions causes shifting of displacement center to one side. Therefore, this paper analyzes both thrust and displacement characteristics and settles the unbalanced flux problem by performing shape optimization. The propriety of the improved design model has been verified by dynamic analysis based on the coupling of kinetic and electric equations.

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Error Estimation Method for Matrix Correlation-Based Wi-Fi Indoor Localization

  • Sun, Yong-Liang;Xu, Yu-Bin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.11
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    • pp.2657-2675
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    • 2013
  • A novel neighbor selection-based fingerprinting algorithm using matrix correlation (MC) for Wi-Fi localization is presented in this paper. Compared with classic fingerprinting algorithms that usually employ a single received signal strength (RSS) sample, the presented algorithm uses multiple on-line RSS samples in the form of a matrix and measures correlations between the on-line RSS matrix and RSS matrices in the radio-map. The algorithm makes efficient use of on-line RSS information and considers RSS variations of reference points (RPs) for localization, so it offers more accurate localization results than classic neighbor selection-based algorithms. Based on the MC algorithm, an error estimation method using artificial neural network is also presented to fuse available information that includes RSS samples and localization results computed by the MC algorithm and model the nonlinear relationship between the available information and localization errors. In the on-line phase, localization errors are estimated and then used to correct the localization results to reduce negative influences caused by a static radio-map and RP distribution. Experimental results demonstrate that the MC algorithm outperforms the other neighbor selection-based algorithms and the error estimation method can reduce the mean of localization errors by nearly half.

The Estrogenic Effects of Methoxychlor in Pubertal Female Rats: Establishment of Thyroid Assay for Endocrine Disruptors (사춘기 암컷 랫드에서 갑상선 시험에 의한 Methoxychlor의 에스트로젠 효과)

  • 정문구;김종춘;임광현
    • Toxicological Research
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    • v.16 no.1
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    • pp.27-31
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    • 2000
  • Recently, there is a worldwide concern that a great number of man-made chemicals have a hormone-like action both in humans and in animals. EPA and OECD are developing screening programs using validated test systems to determine whether certain substances may have an effect on humans. In the present study, the establishment of in vivo short-term test system for pubertal female assay with thyroid to detect endocrine disrupting chemicals was tried using a model substance, methoxychlor (MC), a chlorinated hydrocarbon insencticide. Forty female rats were assigned to four groups. MC was administered at dose levels of 0, 8, 40 and 200mg/kg by gavage to female rats from day 21 post partum to the completion of vaginal opening. We evaluated body weight change, age at vaginal opening, onset of estrous cyclicity, age at first esturs, ovary weight, and serum concentrations of thyroxine and thyroid stimulating hormone in female rats. The age at vaginal opening of females receiving 40 200mg/kg was significantly younger than control. The onset of estrus cyclicity and age at first estrus of females receiving 200mg/kg was also younger than controls. There was no effect of treatment on body weight, ovary weight, and hormone concentration. Based on these results, it can be concluded that application of MC at dose level of 40mg/kg affects the vaginal opening and application of MC at dose level of 200mg/kg accelerates the vaginal opening and the onset of estrus cylicity.

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DYNAMICAL EVOLUTION OF SUPERNOVA REMNANTS BREAKING THROUGH MOLECULAR CLOUDS

  • Cho, Wankee;Kim, Jongsoo;Koo, Bon-Chul
    • Journal of The Korean Astronomical Society
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    • v.48 no.2
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    • pp.139-154
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    • 2015
  • We carry out three-dimensional hydrodynamic simulations of the supernova remnants (SNRs) produced inside molecular clouds (MCs) near their surface using the HLL code (Harten et al. 1983). We explore the dynamical evolution and the X-ray morphology of SNRs after breaking through the MC surface for ranges of the explosion depths below the surface and the density ratios of the clouds to the intercloud media (ICM). We find that if an SNR breaks out through an MC surface in its Sedov stage, the outermost dense shell of the remnant is divided into several layers. The divided layers are subject to the Rayleigh-Taylor instability and fragmented. On the other hand, if an SNR breaks through an MC after the remnant enters the snowplow phase, the radiative shell is not divided to layers. We also compare the predictions of previous analytic solutions for the expansion of SNRs in stratified media with our onedimensional simulations. Moreover, we produce synthetic X-ray surface brightness in order to research the center-bright X-ray morphology shown in thermal composite SNRs. In the late stages, a breakout SNR shows the center-bright X-ray morphology inside an MC in our results. We apply our model to the observational results of the X-ray morphology of the thermal composite SNR 3C 391.

A hybrid MC-HS model for 3D analysis of tunnelling under piled structures

  • Zidan, Ahmed F.;Ramadan, Osman M.
    • Geomechanics and Engineering
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    • v.14 no.5
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    • pp.479-489
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    • 2018
  • In this paper, a comparative study of the effects of soil modelling on the interaction between tunnelling in soft soil and adjacent piled structure is presented. Several three-dimensional finite element analyses are performed to study the deformation of pile caps and piles as well as tunnel internal forces during the construction of an underground tunnel. The soil is modelled by two material models: the simple, yet approximate Mohr Coulomb (MC) yield criterion; and the complex, but reasonable hardening soil (HS) model with hyperbolic relation between stress and strain. For the former model, two different values of the soil stiffness modulus ($E_{50}$ or $E_{ur}$) as well as two profiles of stiffness variation with depth (constant and linearly increasing) were used in attempts to improve its prediction. As these four attempts did not succeed, a hybrid representation in which the hardening soil is used for soil located at the highly-strained zones while the Mohr Coulomb model is utilized elsewhere was investigated. This hybrid representation, which is a compromise between rigorous and simple solutions yielded results that compare well with those of the hardening soil model. The compared results include pile cap movements, pile deformation, and tunnel internal forces. Problem symmetry is utilized and, therefore, one symmetric half of the soil medium, the tunnel boring machine, the face pressure, the final tunnel lining, the pile caps, and the piles are modelled in several construction phases.

Modelling the rheological behaviour of fresh concrete: An elasto-viscoplastic finite element approach

  • Chidiac, S.E.;Habibbeigi, F.
    • Computers and Concrete
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    • v.2 no.2
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    • pp.97-110
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    • 2005
  • Rheological behaviour of fresh concrete is an important factor in controlling concrete quality. It is recognized that the measurement of the slump is not a sufficient test method to adequately characterize the rheology of fresh concrete. To further understand the slump measurement and its relationship to the rheological properties, an elasto-viscoplastic, 2-D axisymmetric finite element (FE) model is developed. The FE model employs the Bingham material model to simulate the flow of a slump test. An experimental program is carried out using the Slump Rate Machine (SLRM_II) to evaluate the finite element simulation results. The simulated slump-versus-time curves are found to be in good agreement with the measured data. A sensitivity study is performed to evaluate the effects of yield stress, plastic viscosity and cone withdrawal rate on the measured flow curve using the FE model. The results demonstrate that the computed yield stress compares well with reported experimental data. The flow behaviour is shown to be influenced by the yield stress, plastic viscosity and the cone withdrawal rate. Further, it is found that the value of the apparent plastic viscosity is different from the true viscosity, with the difference depending on the cone withdrawal rate. It is also confirmed that the value of the final slump is most influenced by the yield stress.

Calculation of Film Diffusion Coefficients and Surface Diffusion Coefficients of Volatile Organic Compounds Using Activated Carbon Adsorption Model and Small Column Test (활성탄 흡착모델과 칼럼실험을 통한 Volatile Organic Compounds의 막확산계수와 표면확산계수의 도출)

  • Lee, Byoung-Ho;Lee, Joon-Hee
    • Journal of Korean Society of Water and Wastewater
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    • v.13 no.1
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    • pp.72-80
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    • 1999
  • Separation of VOCs(Volatile Organic Compounds) in Water Using Activated Carbon is known to be effective. Activated Carbon has been and will be employed in many water treatment plants. Simplified plug flow homogeneous surface diffusion model(PFHSDM) has been used to predict adsorption of organic matter. Finite Element Method(FEM) was used to analyze the model. Out of water quality control substances, benzene, toluene and tetrachloroethylene were used in the small column test. Film diffusion coefficients and surface diffusion coefficients were obtained from the column test, and were compared with the modeling results. Mc Cune, Williamson, William and Kataoka model, were compared with film diffusion coefficients obtained in the test. McCune model was fitted best for those VOCs used in this experiment. Film diffusion coefficients of VOCs obtained were benzene 0.265 cm/min, toluene 0.348 cm/min and tetrachloroethylene 0.298 cm/min. Surface diffusion coefficients of VOCs obtained were benzene $6.36{\times}10^{-8}cm^2/min$, toluene $3.20{\times}10-8cm2/min$, and tetrachloruethylene $4.94{\times}10^{-8}cm^2/min$.

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Performance Analysis of MC-DS/CDMA System with Phase Error and Hybrid SC/MRC-(2/3) Diversity (위상 에러와 하이브리드 SC/MRC-(2/3)기법을 고려한 MC-DS/CDMA 시스템의 성능 분석)

  • Kim Won-Sub;Park Jin-Soo
    • The KIPS Transactions:PartC
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    • v.11C no.6 s.95
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    • pp.835-842
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    • 2004
  • In this paper, we have analyzed the MC-DS/CDMA system with input signal synchronized completely through adjustment of the gain in the PLL loop, by using the hybrid SC/MRC-(2/3) technique, which is said to one of the optimal diversity techniques under the multi-path fading environment, assuming that phase error is defined to the phase difference between the received signal from the multi-path and the reference signal in the PLL of the receiver. Also, assuming that the regarded radio channel model for the mobile communication is subject to the Nakagami-m fading channel, we have developed the expressions and performed the simulation under the consideration of various factor, in the MC/DS-CDMA system with the hybrid SC.MRC-(2/3) diversity method, such as the Nakagami fading index(m), $the\;number\;of\;paths\;(L_p),$ the number of hybrid SC.MRC-(2/3) $diversity\;branches\;(L,\;L_c),$ the number of users (K), the number of subcarriers (U), and the gain in the PLL loop. As a result of the simulation, it has been confirmed that the performance improvement of the system can be achieved by adjusting properly the PLL loop in order for the MC/DS-CDMA system with the hybrid SC/MRC-(2/3) diversity method to receive a fully synchronized signal. And the value of the gain in the PLL loop should exceed 7dB in order for the system to receive the signal with prefect synchronization, even though there might be a slight difference according to the values of the fading index and the spread processing gain of the subcarrier.

Rapid and Precise Determination of Pb Isotope Ratios Using Mu1ti-Collector ICP/MS (다검출기 유도결합 플라즈마 질량분석기를 이용한 신속하고 정밀한 Pb 동위원소 분석)

  • 최만식;정창식;신형선;임태선
    • The Journal of the Petrological Society of Korea
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    • v.10 no.3
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    • pp.157-171
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    • 2001
  • This study investigated the effects of Pb/Tl ratio, Pb concentration and concomitant matrix elements on the measurement of Pb isotope ratios using multi-collector ICP/MS (AXIOM MC model). Accuracy and reproducibility of Pb isotope ratios in NBS 981 solution were estimated for 42 data measured from March to August 2001. Pb isotopes measured in rocks, bronzes and sediments were compared to data measured by TIMS. Reproducibilities for $^{206}Pb/^{204}Pb,\; ^{207}Pb/^{204}Pb,\;and\;^{208}Pb/^{204}Pb$ ratio were about 500 ppm (2sd) and for $^{207}Pb/^{206}Pb$\;and\;^{208}Pb/^{206}Pb$ were 100~200 ppm for 200 ng of Pb in NBS 981 solution. The optimum conditions for the analysis of Pb isotope ratios with AXIOM MC for best accuracy and reproducibility were defined as follows; 1) Pb/Tl ratio is about 10 2) Pb concentration is about 100 ng/ml 3) correction for mass discrimination is performed by exponential law using 2.3887 of $^{205}Tl/^{203}Tl$ and Pb mass fractionation factor empirically obtained from $ln(^{208}Pb/^{206}Pb)-ln(^{205}Tl/^{203}Tl)$ relationship. The sample data measured with MC/ICP/MS for acid-digested and chemically separated rock samples, and acid-digested bronze samples and sediment samples coincide with those of TIMS within analytical errors. Therefore, MC/ICP/MS is a rapid analytical technique for Pb isotope ratios with the similar precision compared with TIMS.

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Effects of Phytoestrogen on Cell Growth and Insulin-like Growth Factor-I (IGF-I) Production in MC3T3-El Cells (식물성 에스트로겐이 MC3T3-El 골아세포의 성장과 Insulin-like Growth Factor-1(IGF-1)생성에 미치는 영향)

  • Kwon, Ji-Young;Nam, Taek-Jeong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.6
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    • pp.743-749
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    • 2005
  • Estrogen is known to play an important role in maintaining bone mass, since the concentration of serum estrogen decrease after menopause and the estrogen deficiency results in bone loss. Phytoestrogens are plant compounds with estrogen-like biological activity, In this study, to investigate the bioactivities of phytoestrogen, which act on bone metabolism, we examined the effect of selected food-borne phytoestrogens (genistein, daidzein and resveratrol) on osteoblast proliferation and IGF-I production using MC3T3-El cells, a mouse calvaria osteoblast-like cell line. Cells were cultured in a serum free medium for 48 hr in the presence of genistein $(10^{-5}\;M)$, daidzein $(10^{-5}\;M)$ and resveratrol $(10^{-5}\;M)$. The effects of genistein, daidzein and resveratrol on the cell proliferation and growth were evaluated by total cell numbers, MTS assay and cell migration assay. Their effect was compared with the $17\beta-estradiol$. Genistein, daidzein and resveratrol exhibited stimulatory effects on the growth of MC3T3-El cells, and the most pronounced effect was shown with daidzein. In addition, these phytoestrogen increased alkaline phosphatase activity of MC3T3-El cells. These effects were similar to that of $17\beta-estradiol$ effects. Moreover, treatment with genistein, daidzein and resveratrol increased production of insulin like growth factor-I (IGF-I) in conditioned media, indicating that the growth promoting effects of these phytoestrogen were related to the changes in production of IGF-I by MC3T3-El cells. These results show that genistein, daidzein and resveratrol have a stimulatory effect on osteoblast function, and that these findings in a cell model may prove relevant to protecting against the loss of bone mass and the development of osteoporosis in human subjects.