共查询到19条相似文献,搜索用时 109 毫秒
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中国工业二氧化硫排放量既是一个灰色系统,又是一个离散动态系统。本文基于GPM(1)灰色生长曲线,建立了预测中国工业二氧化硫排放量的GIPM(1)这一灰色对数幂函数曲线新模型。应用表明,GIPM(1)不仅与实际具有良好的一致性,也为国家制定工业二氧化硫排放量的控制治理规划提供了理论依据。 相似文献
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本文介绍了日本横滨雨水中S(IV)浓度和氧化速率的测定方法:S(IV)在雨水中的氧化反应一组反应;Fe^3+和Mn^2+离子对雨水中S(IV)的氧化有强的催化作用;S(IV)的浓度是0.8~23.5μm和氧化率常数0.12~3.3小时^-1。 相似文献
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1 概况第63届IEC年会于1999年10月17日~29日在日本京都国际会馆举行。出席会议的代表来自52个国家约1400多人,其中中国代表48人。会议期间,60多个技术委员会或分技术委员会分别举行了工作会议和各自的工作组会议,对不同专业领域的国际标准草案进行了认真细致的讨论,并确定了今后的工作计划。在此期间大会组委会还组织到OMRON(欧姆龙)、Kyocera、Matsushita(松下)、Sumitomo(住友)、Sharp(夏普)等日本著名企业进行参观和技术交流。此外,会议期间还安排了一场I… 相似文献
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用气相色谱/质谱(GC/MS)研究分析了环境中的半挥发性有机标准物。以十氟三苯基磷作调机物,对GC/MS仪器系统进行了调整,离子丰度值符合美国环保局(U.S.EPA)1986年推荐的离子丰度标准。测定了32种目标化合物的保留时间及相对保留因子RF值,结果表明除五氯苯酚不达标外,其余化合物的RF值均符合要求,31种目标化合物的加标回收率为21%~97%,相对标准偏差为3.1%~24.1%,符合美国环保局8270方法质量控制检验标准。最后对建立定量校正库与GC/MS分析进行了讨论 相似文献
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西南地区卫星林火监测系统的建立 总被引:2,自引:0,他引:2
本文对建立GIS支持的NOAA卫星林火监测系统进行了分析.内容包括:监测区GIS的形成;NOAA卫星图像叠加经纬度网格;GIS与NOAA卫星图像的复合.1994年春天,我们对西南林区林火进行了1个多月的实时监测,证明了该系统具有林火分辨率高和定位准确的特点.是一个较为理想的林火监测系统。 相似文献
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新型除尘滤袋材料──P_(84)及其复合滤料NEW FILTERBAGMATERIAL──P_(84)ANDITSCOMPOSITEFILTERINGMEDIUMAnewfilterbagmaterial──P_(84)anditscomposite... 相似文献
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Moon Seong Rang Min Goo Kang Seung Woo Park Jeong Jae Lee Ryung Hak Yoo 《Journal of the American Water Resources Association》2006,42(2):473-486
The main focus of this study was to compare the Grey model and several artificial neural network (ANN) models for real time flood forecasting, including a comparison of the models for various lead times (ranging from one to six hours). For hydrological applications, the Grey model has the advantage that it can easily be used in forecasting without assuming that forecast storm events exhibit the same stochastic characteristics as the storm events themselves. The major advantage of an ANN in rainfall‐runoff modeling is that there is no requirement for any prior assumptions regarding the processes involved. The Grey model and three ANN models were applied to a 2,509 km2 watershed in the Republic of Korea to compare the results for real time flood forecasting with from one to six hours of lead time. The fifth‐order Grey model and the ANN models with the optimal network architectures, represented by ANN1004 (34 input nodes, 21 hidden nodes, and 1 output node), ANN1010 (40 input nodes, 25 hidden nodes, and 1 output node), and ANN1004T (14 input nodes, 21 hidden nodes, and 1 output node), were adopted to evaluate the effects of time lags and differences between area mean and point rainfall. The Grey model and the ANN models, which provided reliable forecasts with one to six hours of lead time, were calibrated and their datasets validated. The results showed that the Grey model and the ANN1010 model achieved the highest level of performance in forecasting runoff for one to six lead hours. The ANN model architectures (ANN1004 and ANN1010) that used point rainfall data performed better than the model that used mean rainfall data (ANN1004T) in the real time forecasting. The selected models thus appear to be a useful tool for flood forecasting in Korea. 相似文献
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Jian-Zhou Wang 《International Journal of Green Energy》2017,14(5):463-478
Wind resources are becoming increasingly significant due to their clean and renewable characteristics, and the integration of wind power into existing electricity systems is imminent. To maintain a stable power supply system that takes into account the stochastic nature of wind speed, accurate wind speed forecasting is pivotal. However, no single model can be applied to all cases. Recent studies show that wind speed forecasting errors are approximately 25% to 40% in Chinese wind farms. Presently, hybrid wind speed forecasting models are widely used and have been verified to perform better than conventional single forecasting models, not only in short-term wind speed forecasting but also in long-term forecasting. In this paper, a hybrid forecasting model is developed, the Similar Coefficient Sum (SCS) and Hermite Interpolation are exploited to process the original wind speed data, and the SVM model whose parameters are tuned by an artificial intelligence model is built to make forecast. The results of case studies show that the MAPE value of the hybrid model varies from 22.96% to 28.87 %, and the MAE value varies from 0.47 m/s to 1.30 m/s. Generally, Sign test, Wilcoxon’s Signed-Rank test, and Morgan--Granger--Newbold test tell us that the proposed model is different from the compared models. 相似文献
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运用灰色系统理论,建立了一种非线性GM(l,l^s,t)灰色新模型,并将其应用于某厂SO2排放量的预测之中。结果表明,NLGM(l,l^s,t)具有良好的模型品质,中长期预测定GM(l,l)更可靠。 相似文献
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Wind energy, one of the most promising renewable and clean energy sources, is becoming increasingly significant for sustainable energy development and environmental protection. Given the relationship between wind power and wind speed, precise prediction of wind speed for wind energy estimation and wind power generation is important. For proper and efficient evaluation of wind speed, a smooth transition periodic autoregressive (STPAR) model is developed to predict the six-hourly wind speeds. In addition, the Elman artificial neural network (EANN)-based error correction technique has also been integrated into the new STPAR model to improve model performance. To verify the developed approach, the six-hourly wind speed series during the period of 2000–2009 in the Hebei region of China is used for model construction and model testing. The proposed EANN-STPAR hybrid model has demonstrated its powerful forecasting capacity for wind speed series with complicated characteristics of linearity, seasonality and nonlinearity, which indicates that the proposed hybrid model is notably efficient and practical for wind speed forecasting, especially for the Hebei wind farms of China. 相似文献
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Pao‐Shan Yu Chia‐Jung Chen Shiann‐Jong Chen Shu‐Chen Lin 《Journal of the American Water Resources Association》2001,37(1):151-166
ABSTRACT: A reliable forecasting model is essential in real‐time flood forecasting for reducing natural damage. Efforts to develop a real‐time forecasting model over the past two decades have been numerous. This work applies the Grey model to forecast rainfall and runoff owing to the model's relative ability to predict the future using a small amount of historical data. Such a model significantly differs from the stochastic and deterministic models developed previously. Ten historical storm events from two catchment areas in northern Taiwan are selected to calibrate and verify the model. Results in this study demonstrate that the proposed models can reasonably forecast runoff one to four hours ahead, if the Grey error prediction method is further used to update the output of the model. 相似文献
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本文将地面水质视作灰色系统,对某河段的化学耗氧量(COD),生化耗氧量(BOD_5)用灰色预测模型GM(1,1)进行建模、预测。最大误5.2%,平均误差小于0.2%,模型精度高。建模需要的数据较少,对数据的分布无特殊要求,方法和计算简单,实用价值大,是地面水质预测预报的一种有效方法。 相似文献
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Nabeel R. Mishalani Richard N. Palmer 《Journal of the American Water Resources Association》1988,24(6):1237-1245
ABSTRACT: This research investigates the benefits of forecasting in water supply systems. Questions relating operational losses to forecast period and accuracy are addressed. Some simple available forecasting techniques are assessed for their accuracy and applicability. These issues are addressed through the use of a simulation model of the Cedar and South Fork Tolt Rivers, where the system is modeled as a single purpose reservoir supplying municipal and industrial water to the Seattle metropolitan area. The following conclusions were made for this system: (1) reservoir operation deteriorates markedly with the loss of forecast accuracy; (2) the optimal length of forecasting period is five months; (3) reservoir operation may be improved by as much as 88 percent if perfect predictive abilities are available; (4) the mean of the historic data is not recommended to predict future flows because Markov methods are always superior; and (5) lag-one autoregressive Markov schemes exhibit about a 9 percent improvement in operation over no forecasting. 相似文献
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System dynamics modeling for municipal water demand estimation in an urban region under uncertain economic impacts 总被引:1,自引:0,他引:1
Accurate prediction of municipal water demand is critically important to water utilities in fast-growing urban regions for drinking water system planning, design, and water utility asset management. Achieving the desired prediction accuracy is challenging, however, because the forecasting model must simultaneously consider a variety of factors associated with climate changes, economic development, population growth and migration, and even consumer behavioral patterns. Traditional forecasting models such as multivariate regression and time series analysis, as well as advanced modeling techniques (e.g., expert systems and artificial neural networks), are often applied for either short- or long-term water demand projections, yet few can adequately manage the dynamics of a water supply system because of the limitations in modeling structures. Potential challenges also arise from a lack of long and continuous historical records of water demand and its dependent variables. The objectives of this study were to (1) thoroughly review water demand forecasting models over the past five decades, and (2) propose a new system dynamics model to reflect the intrinsic relationship between water demand and macroeconomic environment using out-of-sample estimation for long-term municipal water demand forecasts in a fast-growing urban region. This system dynamics model is based on a coupled modeling structure that takes into account the interactions among economic and social dimensions, offering a realistic platform for practical use. Practical implementation of this water demand forecasting tool was assessed by using a case study under the most recent alternate fluctuations of economic boom and downturn environments. 相似文献