• Title/Summary/Keyword: Statistical estimation

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Estimation of Environmental Performance in 29 Chinese Provinces - Focused on Integrated Pollution Intensity - (중국 29개 성의 환경성과 평가 - 통합오염원 단위를 중심으로 -)

  • Kim, Kwang-Uk;Piao, Huilan-Lan;Kang, Sang-Mok
    • Journal of Environmental Policy
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    • v.10 no.1
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    • pp.71-91
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    • 2011
  • The purpose of this paper is to estimate the environmental performance of 29 Chinese provinces by adopting the advanced measurements, integrated pollution intensity index, IPI, which can be computed using Data Envelopment Analysis(DEA) techniques. This index has the advantage of accounting for multiple resources used, good outputs produced and pollutants emitted simultaneously. The result obtained using the methodology shows the obvious evidence that provinces located around eastern area of China take relatively low levels and these phenomenons have been clearly observed throughout the sample period 1998~2007. The estimated index can be interpreted that the environmental burden in China has been steadily decreased as economic growth. This paper also tries to figure out the relationship among IPI, income levels, economic structures, the level of environmental regulations and FDI inflow. The estimated relationship between IPI and income per capita predicts improving environmental performance with increasing income levels. This explains the improvement in IPI which is simultaneously observed with income increases. According to the 'pollution haven hypothesis', many researches have been concerned the possibility that a large amount of foreign capital has been invested in China to avoid the strict environmental standards in advanced countries. However, the estimated coefficients in all model specifications take negative sign with IPI and highly statistical significant. This is a indication that there are positive impacts of foreign investments on IPI by adopting clean and high technologies from advanced countries.

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Profiling Stress History(OCR, $\sigma를$p) of Marine Clay Using Piezocone Penetration Test (해성점토지반에서 CPT를 이용한 응력이력(OCR, $\sigma$를 p)의 산정)

  • 이강운;윤길림;채영수
    • Journal of the Korean Geotechnical Society
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    • v.18 no.6
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    • pp.73-81
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    • 2002
  • Various CPT-based prediction models far profiling stress history of marine clay at the southern part of the Korean peninsula were investigated by using both statistical analysis and case history study. Preconsolidation pressures($\sigma'$p) and overconsolidation ratio(OCR) estimated by empirical correlations and cone penetration tests were compared with those of laboratory odometer test results. Stress history of marine clay determined by odometer test results was in general overconsolidated at below 10m depth from the mudline, whereas marine clay at below l0m depth from the mudline which has an around 0.3 overconsolidation ratio showed variable stresses and unstable states. Preconsolidation pressures were computed by both empirical methods of the Chen and Mayne(1996) and theoretical method of Konrad and Law(1987). It is estimated that Chen and Mayne(1996)'s prediction method based on pore water pressure is more reliable than any other prediction methods, and their method proved to be the most reliable for overconsolidation ratio estimation. However, it is recommended that Mayne & Holtz(1988) and Mayne & Bachus(1988) methods are more suitable than any other methods for predicting the overconsolidation ratio at an underconsolidated (OCR<1) clay. For these reasons, rather than making use of existing prediction models, development of site specific empirical correlations which considers local characteristics and site conditions may be required due to different local stress history and variable soil properties.

Comparison of Forest Growing Stock Estimates by Distance-Weighting and Stratification in k-Nearest Neighbor Technique (거리 가중치와 층화를 이용한 최근린기반 임목축적 추정치의 정확도 비교)

  • Yim, Jong Su;Yoo, Byung Oh;Shin, Man Yong
    • Journal of Korean Society of Forest Science
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    • v.101 no.3
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    • pp.374-380
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    • 2012
  • The k-Nearest Neighbor (kNN) technique is popularly applied to assess forest resources at the county level and to provide its spatial information by combining large area forest inventory data and remote sensing data. In this study, two approaches such as distance-weighting and stratification of training dataset, were compared to improve kNN-based forest growing stock estimates. When compared with five distance weights (0 to 2 by 0.5), the accuracy of kNN-based estimates was very similar ranged ${\pm}0.6m^3/ha$ in mean deviation. The training dataset were stratified by horizontal reference area (HRA) and forest cover type, which were applied by separately and combined. Even though the accuracy of estimates by combining forest cover type and HRA- 100 km was slightly improved, that by forest cover type was more efficient with sufficient number of training data. The mean of forest growing stock based kNN with HRA-100 and stratification by forest cover type when k=7 were somewhat underestimated ($5m^3/ha$) compared to statistical yearbook of forestry at 2011.

Genetic Contribution of Indigenous Yakutian Cattle to Two Hybrid Populations, Revealed by Microsatellite Variation

  • Li, M.H.;Nogovitsina, E.;Ivanova, Z.;Erhardt, G.;Vilkki, J.;Popov, R.;Ammosov, I.;Kiselyova, T.;Kantanen, J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.5
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    • pp.613-619
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    • 2005
  • Indigenous Yakutian cattle' adaptation to the hardest subarctic conditions makes them a valuable genetic resource for cattle breeding in the Siberian area. Since early last century, crossbreeding between native Yakutian cattle and imported Simmental and Kholmogory breeds has been widely adopted. In this study, variations at 22 polymorphic microsatellite loci in 5 populations of Yakutian, Kholmogory, Simmental, Yakutian-Kholmogory and Yakutian-Simmental cattle were analysed to estimate the genetic contribution of Yakutian cattle to the two hybrid populations. Three statistical approaches were used: the weighted least-squares (WLS) method which considers all allele frequencies; a recently developed implementation of a Markov chain Monte Carlo (MCMC) method called likelihood-based estimation of admixture (LEA); and a model-based Bayesian admixture analysis method (STRUCTURE). At population-level admixture analyses, the estimate based on the LEA was consistent with that obtained by the WLS method. Both methods showed that the genetic contribution of the indigenous Yakutian cattle in Yakutian-Kholmogory was small (9.6% by the LEA and 14.2% by the WLS method). In the Yakutian-Simmental population, the genetic contribution of the indigenous Yakutian cattle was considerably higher (62.8% by the LEA and 56.9% by the WLS method). Individual-level admixture analyses using STRUCTURE proved to be more informative than the multidimensional scaling analysis (MDSA) based on individual-based genetic distances. Of the 9 Yakutian-Simmental animals studied, 8 showed admixed origin, whereas of the 14 studied Yakutian-Kholmogory animals only 2 showed Yakutian ancestry (>5%). The mean posterior distributions of individual admixture coefficient (q) varied greatly among the samples in both hybrid populations. This study revealed a minor existing contribution of the Yakutian cattle in the Yakutian-Kholmogory hybrid population, but in the Yakutian-Simmental hybrid population, a major genetic contribution of the Yakutian cattle was seen. The results reflect the different crossbreeding patterns used in the development of the two hybrid populations. Additionally, molecular evidence for differences among individual admixture proportions was seen in both hybrid populations, resulting from the stochastic process in crossing over generations.

Risk of Breast Cancer and Total Malignancies in Rheumatoid Arthritis Patients Undergoing TNF-α Antagonist Therapy: a Meta-analysis of Randomized Control Trials

  • Liu, Yang;Fan, Wei;Chen, Hao;Yu, Ming-Xia
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.8
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    • pp.3403-3410
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    • 2014
  • Context: Interest exits in whether TNF-alpha antagonists increase the risk of breast cancer and total malignancies in patients with rheumatoid arthritis (RA). Objectives: To analyze the risk of malignancies, especially breast cancer, in patients with RA enrolled in randomized control trials (RCTs). Methods: A systematic literature search for RCTs from 1 January 1998 to 1 July 2013 from online databases, such as PubMed, WILEY, EMBASE, ISI web of knowledge and Cochrane Library was conducted. Studies included RCTs that compared the safety of at least one dose of the five TNF-${\alpha}$ antagonists with placebo or methotrexate (MTX) (or TNF-${\alpha}$ antagonists plus MTX vs placebo plus MTX) in RA patients for more than 24 weeks and imported all the references into document management software EndNote${\times}6$. Two independent reviewers selected studies and extracted the data about study design, patients' characteristics and the type, number of all malignancies. Results: 28 RCTs from 34 records with 11,741 patients were analyzed. Of the total, 97 developed at least one malignancy during the double-blind trials, and breast cancer was observed in 17 patients (17.5% of total malignancies). However, there was no statistically significant increased risk observed in either the per protocol (PP) model (OR 0.65, 95%CI [0.22, 1.93]) or the modified intention to treat (mITT) model (OR 0.75, 95%CI [0.25, 2.21]). There were also no significant trend for increased risk of total malignancies on anti-TNF-${\alpha}$ therapy administered at approved doses in either model (OR, 1.06, 95%CI [0.64, 1.75], and OR, 1.30, 95%CI [0.80, 2.14], respectively). As to the two models, modified intention to treat model analysis led to higher estimation than per protocol model analysis. Conclusions: This study did not find a significantly increased risk of breast cancer and total malignancies in adults RA patients treated with TNF-${\alpha}$ antagonists at approved doses. However, it cannot be ignored that more patients developed malignancies with TNF-${\alpha}$ antagonists therapy compared with patients with placebo or MTX, in spite of the lack of statistical significance, so that more strict clinical trials and long-term follow-up are needed, and both mITT and PP analyses should be used in such safety analyses.

Capacity of Urban Freeway Work Zones (도시 고속도로 공사구간 용량 산정)

  • Lee, Mi Ri;Kim, Do-Gyeong;Kim, Hyo-Seung;Lee, Chungwon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.1123-1130
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    • 2013
  • This paper aims to estimate work zone base capacity by the number of lanes for urban freeway. To do this, data were collected from the field survey and the database system maintained by traffic control center, and analyzed with four different methods such as the average maximum observation flow rate, headway, regression analysis, and parameter inspection. The work zone base capacity for urban freeway is estimated based on the average maximum observation flow rate and headway method, which are more reliable methods compared to others. The average capacity is 1,650pcphpl when the design speed is 80km/h. The capacity of four lanes one-way work zones was about 1,700pcphpl, while one of 2 lanes one-way work zones was about 1,600pcphpl. The capacity reduction rates for each are 0.15 and 0.2, respectively. The smaller the number of lane is, the more base capacity is reduced. For verification of results, we estimate the capacity by simulation analysis using PARAMICS, and compare with analytical results by a statistical method. This research can be used for efficient and systemic management of work zone in the urban freeway.

P53 Arg72Pro Polymorphism and Bladder Cancer Risk - Meta-analysis Evidence for a Link in Asians but not Caucasians

  • Xu, Ting;Xu, Zi-Cheng;Zou, Qin;Yu, Bin;Huang, Xin-En
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.2349-2354
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    • 2012
  • Objective: Individual studies of the associations between P53 codon 72 polymorphism (rs1042522) and bladder cancer susceptibility have shown inconclusive results. To derive a more precise estimation of the relationship, we performed this systemic review and meta-analysis based on 15 publications. Methods: We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Results: We found that there was no association between P53 codon 72 polymorphism and bladder cancer risk in the comparisons of Pro/Pro vs Arg/Arg; Pro/Arg vs. Arg/Arg; Pro/Pro plus Pro/Arg vs. Arg/Arg; Arg/Arg vs. Pro/Arg plus Arg/Arg (OR=1.06 95%CI 0.81-1.39; OR=1.06 95%CI 0.83-1.36; OR=0.98 95%CI 0.78-1.23; OR=1.06 95%CI 0.84-1.32). However, a significantly increased risk of bladder cancer was found among Asians in the homozygote comparison (Pro/Pro vs. Arg/Arg, OR=1.36 95%CI 1.05-1.75, P=0.790 for heterogeneity) and the dominant model (Arg/Pro plus Pro/Pro vs. Arg/Arg, OR=1.26 95%CI 1.05-1.52, P=0.564 for heterogeneity). In contrast, no evidence of an association between bladder cancer risk and P53 genotype was observed among Caucasian population in any genetic model. When stratifying for the stage of bladder, no statistical association were found (Pro/Pro vs. Arg/Arg, OR=0.45 95%CI 0.17-1.21; Pro/Arg vs. Arg/Arg, OR=0.60 95%CI 0.28-1.27; Dominant model, OR=0.56 95%CI 0.26-1.20; Recessive model, OR=0.62 95%CI0.35-1.08) between P53 codon 72 polymorphism and bladder cancer in all comparisons. Conclusions: Despite the limitations, the results of the present meta-analysis suggest that, in the P53 codon 72, Pro/Pro type and dominant mode might increase the susceptibility to bladder cancer in Asians; and there are no association between genotype distribution and the stage of bladder cancer.

Statistical Genetic Studies on Cattle Breeding for Dairy Productivity in Bangladesh: II. Estimation of Reciprocal and Heterosis Effects and Optimum Crossbreeding System between the Local Breeds and Exotic Breeds for Milk Performance

  • Hossain, K.B.;Takayanagi, S.;Miyake, T.;Bhuiyan, A.K.F.H.;Sasaki, Y.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.6
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    • pp.777-782
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    • 2002
  • Reciprocal effects among local breeds and additive and heterosis effects were estimated for total milk production per lactation (TLP), lactation length (LL) and daily milk yield (DMY). Procedures for an optimum crossbreeding system were examined by comparing various crossbred combinations. Three data sets were chosen from the total records collected from 1962 to 1997. Data set I with a total of 5,938 records composed of 9 breed groups for reciprocal crosses, data set II with a total of 6,064 records composed of 5 breed groups for additive and heterosis effects and data set III with a total of 10,319 records composed of 42 breed groups for optimum crossbreeding system were analyzed. The least squares ANOVA was used. The reciprocal crosses between Red Sindhi and the Bangladeshi Local showed significant difference. When the Red Sindhi was used as cow, the cross was superior to the opposite in terms of the three performance traits. The results showed that additive breed effects on both TLP and DMY were positive and highly significant between Bos indicus and Bos taurus, whereas the individual heterosis effects were not significant. In general, any local breeds were improved two to three times by crossing with the Friesian once or twice. However, the effect was reduced when the grading up with the Friesian was repeated more than twice. On the other hand, when the local breed was crossed with the other breeds such as Holstein and Jersey, the improvement of TLP was less. Crossing the F1 cows with the Friesian bull gave further improvement. Almost the same trends were found also for LL and DMY. The local breeds and their crosses are raised mainly for draft animals, then it is recommended that the crossbreds between the local cows and Friesian are used for dairy purposes and more than 75% Friesian blood is used for beef.

Identification of Uncertainty in Fitting Rating Curve with Bayesian Regression (베이지안 회귀분석을 이용한 수위-유량 관계곡선의 불확실성 분석)

  • Kim, Sang-Ug;Lee, Kil-Seong
    • Journal of Korea Water Resources Association
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    • v.41 no.9
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    • pp.943-958
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    • 2008
  • This study employs Bayesian regression analysis for fitting discharge rating curves. The parameter estimates using the Bayesian regression analysis were compared to ordinary least square method using the t-distribution. In these comparisons, the mean values from the t-distribution and the Bayesian regression are not significantly different. However, the difference between upper and lower limits are remarkably reduced with the Bayesian regression. Therefore, from the point of view of uncertainty analysis, the Bayesian regression is more attractive than the conventional method based on a t-distribution because the data size at the site of interest is typically insufficient to estimate the parameters in rating curve. The merits and demerits of the two types of estimation methods are analyzed through the statistical simulation considering heteroscedasticity. The validation of the Bayesian regression is also performed using real stage-discharge data which were observed at 5 gauges on the Anyangcheon basin. Because the true parameters at 5 gauges are unknown, the quantitative accuracy of the Bayesian regression can not be assessed. However, it can be suggested that the uncertainty in rating curves at 5 gauges be reduced by Bayesian regression.

Estimation and assessment of long-term drought outlook information using the long-term forecasting data (장기예보자료를 활용한 장기 가뭄전망정보 산정 및 평가)

  • So, Jae-Min;Oh, Taesuk;Bae, Deg-Hyo
    • Journal of Korea Water Resources Association
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    • v.50 no.10
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    • pp.691-701
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    • 2017
  • The objective of this study is to evaluate the long-term drought outlook information based on long-term forecast data for the 2015 drought event. In order to estimate the Standardized Precipitation Index (SPI) for different durations (3-, 6-, 9-, 12-months), we used the observation precipitation of 59 Automated Synoptic Observing System (ASOS) sites, forecast and hindcast data of GloSea5. The Receiver Operating Characteristic (ROC) analysis and statistical analysis (Correlation Coefficient, CC; Root Mean Square Error, RMSE) were used to evaluate the utilization of drought outlook information for the forecast lead-times (1~6months). As a result of ROC analysis, ROC scores of SPI(3), SPI(6), SPI(9) and SPI(12) were estimated to be over 0.70 until the 2-, 3-, 4- and 5-months. The CC and RMSE values of SPI(3), SPI(6), SPI(9) and SPI(12) for forecast lead-time were estimated as (0.60, 0.87), (0.72, 0.95), (0.75, 0.95) and (0.77, 0.89) until the 2-, 4-, 5- and 6-months respectively.