• Title/Summary/Keyword: coefficient-based method

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Uncertainty Analysis of Wave Forces on Upright Sections of Composite Breakwaters (혼성제 직립벽에 작용하는 파력의 불확실성 해석)

  • Lee, Cheol-Eung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.3
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    • pp.258-264
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    • 2011
  • A MCS technique is represented to stochastically analyze the uncertainties of wave forces exerted on the upright sections of composite breakwaters. A stochastical models for horizontal and uplift wave forces can be straightforwardly formulated as a function of the probabilistic characteristics of maximum wave height. Under the assumption of wave forces followed by extreme distribution, the behaviors of relative wave forces to Goda's wave forces are studied by the MCS technique. Double-truncated normal distribution is applied to take the effects of uncertainties of scale and shape parameters of extreme distribution into account properly. Averages and variances of relative wave forces are quantitatively calculated with respect to the exceedance probabilities of maximum design wave height. It is found that the averages of relative wave forces may be decreased consistently with the increases of the exceedance probabilities. In particular, the averages on uplift wave force are evaluated slightly larger than those on horizontal wave force, but the variations of coefficient of the former are adversely smaller than those of the latter. It means that the uncertainties of uplift wave forces are smaller than those of horizontal wave forces in the same condition of the exceedance probabilities. Therefore, the present results could be useful to the reliability based-design method that require the statistical properties about the uncertainties of wave forces.

HPLC-based Analysis of Biogenic Amines in Aging-Cheese (HPLC를 이용한 숙성치즈로부터 바이오제닉 아민 분석법 개발)

  • Park, Jong-Hyuk;Lee, Sang-Cheon;Moon, Hye-Jung;Oh, Jeon-Hui;Song, Gi-Bong
    • Journal of Dairy Science and Biotechnology
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    • v.34 no.3
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    • pp.187-191
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    • 2016
  • Biogenic amines have been used as chemical indicators of fermented foods. So far, several chromatography methods have been developed to detect biogenic amines in foods. However, few methods have identified these compound in domestic cheese. We analyzed the biogenic amines (histamine dihydrochloride, tyramine hydrochloride, ${\beta}$-phenylethylamine hydrochloride, putrescine dihydrochloride, cadaverine, spermidine, tryptamine hydrochloride, ethanolamine hydrochloride and butylamine) in cheese by using HPLC. The calibration curves of the biogenic amines were found to be linear over the concentration range of 10-50 ppm with a correlation coefficient of above 0.99. The limit of detection (LOD) and limit of quantitation (LOQ) of the biogenic amines in the given order were 3.7 and 11.3 ppm, 3.4 and 10.4ppm, 3.4 and 10.3 ppm, 4.0 and 12.2 ppm, 3.4 and 10.4 ppm, 3.4 and 10.5 ppm, 3.5 and 10.7 ppm, 4.1 and 12.5 ppm, and 3.4 and 10.4 ppm, respectively. Recovery rates of the biogenic amines in the given order were 112, 104, 93, 108, 91, 102, 101, and 92%, respectively. The findings of this study suggest that HPLC is a suitable method for the determination of biogenic amines, thereby indicating its potential application in the quality control of aging cheese.

The furulamelllal study in order to obtain the hydrological design basis for hydrological structures in Korea (Run ofl estimate and Flood part) (한국에 있어서 제수문구조물의 설계의 기준을 주기 위한 수문학적 연구(류거, 홍수 편))

  • 박성우
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.8 no.1
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    • pp.1011-1034
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    • 1966
  • This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

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Novel Radix-26 DF IFFT Processor with Low Computational Complexity (연산복잡도가 적은 radix-26 FFT 프로세서)

  • Cho, Kyung-Ju
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.1
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    • pp.35-41
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    • 2020
  • Fast Fourier transform (FFT) processors have been widely used in various application such as communications, image, and biomedical signal processing. Especially, high-performance and low-power FFT processing is indispensable in OFDM-based communication systems. This paper presents a novel radix-26 FFT algorithm with low computational complexity and high hardware efficiency. Applying a 7-dimensional index mapping, the twiddle factor is decomposed and then radix-26 FFT algorithm is derived. The proposed algorithm has a simple twiddle factor sequence and a small number of complex multiplications, which can reduce the memory size for storing the twiddle factor. When the coefficient of twiddle factor is small, complex constant multipliers can be used efficiently instead of complex multipliers. Complex constant multipliers can be designed more efficiently using canonic signed digit (CSD) and common subexpression elimination (CSE) algorithm. An efficient complex constant multiplier design method for the twiddle factor multiplication used in the proposed radix-26 algorithm is proposed applying CSD and CSE algorithm. To evaluate performance of the previous and the proposed methods, 256-point single-path delay feedback (SDF) FFT is designed and synthesized into FPGA. The proposed algorithm uses about 10% less hardware than the previous algorithm.

Subband Sparse Adaptive Filter for Echo Cancellation in Digital Hearing Aid Vent (디지털 보청기 벤트 반향제거를 위한 부밴드 성긴 적응필터)

  • Bae, Hyeonl-Deok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.5
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    • pp.538-542
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    • 2018
  • Echo generated in digital hearing aid vent give rise to user's discomfort. For cancelling feedback echo in vent, it is required to estimate vent impulse response exactly. The vent impulse response has time varying and sparse characteristics. The IPNLMS has been known a useful adaptive algorithm to estimate vent impulse response with these characteristics. In this paper, subband sparse adaptive filter which applying IPNLMS to subband hearing aid structure is proposed to cancel echo of vent by estimating sparse vent impulse response. In the propose method, the decomposition of input signal to subband can pre-whiten each subband signal, so adaptive filter convergence speed can be improved. And the poly phase component decomposition of adaptive filter increases sparsity of each components, and the better echo cancellation can be possible without additional computation. To derive coefficients update equation of the adaptive filter, by defining the cost function based weight NLMS is defined, and the coefficient update equation of each subband is derived. For verifying performances of the adaptive filter, convergence speed, and steady state error by white signal input, and echo cancelling results by real speech input are evaluated by comparing conventional adaptive filters.

Robust parameter set selection of unsteady flow model using Pareto optimums and minimax regret approach (파레토 최적화와 최소최대 후회도 방법을 이용한 부정류 계산모형의 안정적인 매개변수 추정)

  • Li, Li;Chung, Eun-Sung;Jun, Kyung Soo
    • Journal of Korea Water Resources Association
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    • v.50 no.3
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    • pp.191-200
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    • 2017
  • A robust parameter set (ROPS) selection framework for an unsteady flow model was developed by combining Pareto optimums obtained by outcomes of model calibration using multi-site observations with the minimax regret approach (MRA). The multi-site calibration problem which is a multi-objective problem was solved by using an aggregation approach which aggregates the weighted criteria related to different sites into one measure, and then performs a large number of individual optimization runs with different weight combinations to obtain Pareto solutions. Roughness parameter structure which can describe the variation of Manning's n with discharges and sub-reaches was proposed and the related coefficients were optimized as model parameters. By applying the MRA which is a decision criterion, the Pareto solutions were ranked based on the obtained regrets related to each Pareto solution, and the top-rated one due to the lowest aggregated regrets of both calibration and validation was determined as the only ROPS. It was found that the determination of variable roughness and the corresponding standardized RMSEs at the two gauging stations varies considerably depending on the combinations of weights on the two sites. This method can provide the robust parameter set for the multi-site calibration problems in hydrologic and hydraulic models.

Probabilistic Medium- and Long-Term Reservoir Inflow Forecasts (I) Long-Term Runoff Analysis (확률론적 중장기 댐 유입량 예측 (I) 장기유출 해석)

  • Bae, Deg-Hyo;Kim, Jin-Hoon
    • Journal of Korea Water Resources Association
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    • v.39 no.3 s.164
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    • pp.261-274
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    • 2006
  • This study performs a daily long-term runoff analysis for 30 years to forecast medium- and long-term probabilistic reservoir inflows on the Soyang River basin. Snowmelt is computed by Anderson's temperature index snowmelt model and potenetial evaporation is estimated by Penman-combination method to produce input data for a rainfall-runoff model. A semi-distributed TOPMODEL which is composed of hydrologic rainfall-runoff process on the headwater-catchment scale based on the original TOPMODEL and a hydraulic flow routing model to route the catchment outflows using by kinematic wave scheme is used in this study It can be observed that the time variations of the computed snowmelt and potential evaporation are well agreed with indirect observed data such as maximum snow depth and small pan evaporation. Model parameters are calibrated with low-flow(1979), medium-flow(1999), and high-flow(1990) rainfall-runoff events. In the model evaluation, relative volumetric error and correlation coefficient between observed and computed flows are computed to 5.64% and 0.91, respectively. Also, the relative volumetric errors decrease to 17% and 4% during March and April with or without the snowmelt model. It is concluded that the semi-distributed TOPMODEL has well performance and the snowmelt effects for the long-term runoff computation are important on the study area.

Measuring Quality of Life in Cerebral Palsy Children According to the Severity Using the Visual Analogue Scale, Time Trade-Off, and EQ-5D-Y Proxy (뇌성마비 환아 중증도별 시각화척도, 시간교환법, EQ-5D-Y Proxy를 이용한 삶의 질 측정)

  • Lee, Go-Eun;Kim, Nam Kwen;Yun, Young Ju;Wang, Hye Min;Kim, Jeong Hun;Lee, Dong Hyo
    • Journal of Oriental Neuropsychiatry
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    • v.28 no.2
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    • pp.49-59
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    • 2017
  • Objectives: To measure the quality of life in patients according to virtual cerebral palsy severity by using the Korean version of EQ-5D-Y proxy, Visual Analogue Scale (VAS), and Time Trade-Off method (TTO). Methods: The study was conducted in parents of children and adolescents aged 4 to 15 years in Seoul. We analyzed the difference in the utility value according to five levels of cerebral palsy severity in the Gross Motor Function Classification System (GMFCS) and test-retest reliability. Results: 1. There were significant differences in VAS, TTO, and EQ-5D-Y proxy according to the cerebral palsy severity (p<.001). 2. VAS was significantly different according to the respondent's visit to the medical institution, the presence of disease in the respondent, a visit to the child's medical institution, the age of the child, and the sex of the child. The value of TTO was significantly different according to the respondent's visit to the medical institution, respondent's sex, and the age of the child. Also, EQ-5D-Y proxy was significantly different according to the age of the child. 3. Intraclass correlation coefficient values were more than 0.6 for both VAS and TTO at all stages. But for the EQ-5D-Y proxy, the value was less than 0.6 at all stages. Conclusions: The quality of life assessment using EQ-5D-Y proxy showed significant differences in the severity of cerebral palsy. However, large-scale studies using EQ-5D-Y proxy are needed because of low test-retest reliability.

Bioequivalence of Two Clarithromycin Tablets (클래리스로마애신 정제의 생물학적 동등성 평가)

  • 김종국;이사원;최하곤;고종호;이미경;김인숙
    • Biomolecules & Therapeutics
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    • v.6 no.2
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    • pp.219-224
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    • 1998
  • The bioequivalence of two clarithromvcin products was evaluated with 16 normal male volunteers (age 23-28 yr, body weight 57.5-75.517g) following single oral dose. Test product was ReYon Clarithromycin tablets (ReYon Pharm. Corp., Korea) and reference product was Klarici $d_{R}$ tablets (Abbott Korea). Both products contain 250 mg of clarithromucin. One tablet of the test or the reference product was administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). The determination of clarithromycin was accomplished using a modified agar well diffusion bioassay. As a result of the assay validation, the quantification of clarithromycin in human serum by this technique was possible down to 0.03$\mu$g/ml using 100$\mu$l of serum. The coefficient of variation (C.V.) was less than 10%. Average drug concentrations at each sampling time and pharmacokinetic parameters calculated were not significantly different between two products P>0.05); the area under the curve to last sampling time (24 hr) (AU $Co_{24hr}$ (8.10$\pm$ 1.26 vs 8.22$\pm$ 1.627g . hr/ml), AUC from time zero to infinite (AU $Co_{\infty}$) (8.61 $\pm$ 1.28 vs 8.84$\pm$ 1.71 $\mu$g . hr/ml), maximum plasma concentration ( $C_{msx}$) (0.87$\pm$0.22 vs 0.88$\pm$0.19 $\mu$g/ml) and time to maximum plasma concentration ( $T_{max}$) (2.69 $\pm$0.48 vs 2.56$\pm$ 0.51 hr). The differences of mean AU $Co_{24h}$, $C_{msx}$ and $T_{msx}$ between the two products (1.44, 1.39, and 4.65%, respectively) were less than 20%. The power (1-$\beta$) and treatment difference ($\Delta$) for AU $Co_{24hr}$, and $C_{max}$ were more than 0.8 and less than 0.2, respectivly. Although the power for $T_{max}$ was under 0.8, $T_{max}$. of the two products was not significantly different each other (p>0.05). These results suggest that the bioavailability of ReYon Clarithromycin tablets is not significantly different from that of Klarici $d_{R}$ tablets. Therefore, two products are bioequivalent based on the current results. results.sults.sults.s.s.s.s.s.s.s.

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Synthesis and Properties of Nonlinear Optical Polymer Derived from α-Methyl Styrene/Maleic Anhydride by Polymer Reaction (고분자 반응을 이용한 Maleic anhydride계 비선형 광학 고분자의 합성 및 전기광학 특성)

  • Park, Lee Soon;Keum, Chang Dae;Song, Jae Won;Kim, Kwang Taek;Kim, Gi Heon;Kang, Shin Won
    • Applied Chemistry for Engineering
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    • v.9 no.5
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    • pp.704-709
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    • 1998
  • Non-linear optical polymer based on poly (${\alpha}$-methylstyrene-co-maleic anhydride) (MSMA) substrate polymer was prepared by polymer reaction method and its thermal and electro-optic properties were examined. In the polymer reaction between MSMA substrate polymer and 2-[4-(4-nitrophenylazo)-N-ethylphenylamino]ethanol (DR1) chromophore, the degree of substitution of DR1 into MSMA was higher with the 4-dimethylaminopyridine (DMAP) as catalyst and 3-dicyclohexyl carbodiimide (DCC) as dehydrating agent (sample, MSMA-DC) than the one with just 4-dimethylaminopyridine as catalyst (sample, MSMA-D). The synthesized NLO polymer (MSMA-DC) exhibited electro-optic coefficient of 18 pm/V (632.8 nm) and glass transition temperature ($T_g$) of about $175^{\circ}C$.

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