期刊文献+
共找到1,948篇文章
< 1 2 98 >
每页显示 20 50 100
用插值的粗粒化Box Model进行学习控制 被引量:2
1
作者 刘斌 张承福 《自动化学报》 EI CSCD 北大核心 1996年第1期101-106,共6页
针对一类未知动力学方程的单输入系统,采用插值的粗粒化 Box M odel进行学习控制.与传统的Box Model及基于随机元胞自动机的控制模式比较,本模型设计思想自然,算法简单.计算量小(常常小几个数量级),训练时间短。
关键词 学习控制 随机元胞自动机 插值 反馈镇定
下载PDF
Numerical study on the ozone formation inside street canyons using a chemistry box model 被引量:2
2
作者 Chun-Ho Liu Dennis Y.C.Leung 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第7期832-837,共6页
Tropospheric ozone is a secondary air pollutant produced in the presence of nitrogen oxides (NO_x),volatile organic compounds (VOCs),and solar radiation.In an urban environment,ground-level vehicular exhaust is the ma... Tropospheric ozone is a secondary air pollutant produced in the presence of nitrogen oxides (NO_x),volatile organic compounds (VOCs),and solar radiation.In an urban environment,ground-level vehicular exhaust is the major anthropogenic source of ozone precursors.In the cases of street canyons,pollutant dilution is weakened by the surrounding buildings that creates localized high concentration of NO_x and VOCs,and thus leads to high potential of ozone formation.By considering the major physical and chemical p... 展开更多
关键词 volatile organic compounds VOCs-to-NO_x ratio air quality vehicular emission chemistry box model
下载PDF
Nutrient fluxes in the Changjiang River estuary and adjacent waters——a modified box model approach 被引量:1
3
作者 王晓红 俞志明 +3 位作者 樊伟 宋秀贤 曹西华 袁涌铨 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第1期176-193,共18页
To solve nutrient flux and budget among waters with distinct salinity difference for water-salt- nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the tradition... To solve nutrient flux and budget among waters with distinct salinity difference for water-salt- nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang (Yangtze) River estuary (CRE) and adjacent waters (30.75°-31.75°N, 122°10′-123°20′E). Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model (ROMS). Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction (upwelling flux and upward diffusion flux regions overlap largely all the year). Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP (dissolved inorganic phosphate) occurs in summer. Additional to the fluxes of the ChanNiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional one in estimating nutrient fluxes in a complicated hydrodynamic current system and provides a modified box model approach to material flux research. 展开更多
关键词 NUTRIENT box model HYDRODYNAMIC Changjiang (Yangtze) River estuary
下载PDF
Lateral downslope transport and tentative sedimentary organic carbon box model in the southern Yap Trench,western Pacific Ocean 被引量:1
4
作者 Dong Li Jun Zhao +2 位作者 Chenggang Liu Jianming Pan Ji Hu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第1期61-74,共14页
Sediment collapse and subsequent lateral downslope migration play important roles in shaping the habitats and regulating sedimentary organic carbon(SOC)cycling in hadal trenches.In this study,three sediment cores were... Sediment collapse and subsequent lateral downslope migration play important roles in shaping the habitats and regulating sedimentary organic carbon(SOC)cycling in hadal trenches.In this study,three sediment cores were collected using a human-occupied vehicle across the axis of the southern Yap Trench(SYT).The total organic carbon(TOC)and total nitrogen(TN)contents,δ13C,radiocarbon ages,specific surface areas,and grain size compositions of sediments from three cores were measured.We explored the influence of the lateral downslope transport on the dispersal of the sediments and established a tentative box model for the SOC balance.In the SYT,the surface TOC content decreased with water depth and was decoupled by the funneling effect of the V-shaped hadal trench.However,the sedimentation(0.0025 cm/a)and SOC accumulation rates(∼0.038 g/(m^(2)·a)(in terms of OC))were approximately 50%higher in the deeper hadal region than in the abyssal region(0.0016 cm/a and∼0.026 g/(m^(2)·a)(in terms of OC),respectively),indicating the occurrence of lateral downslope transport.The fluctuating variations in the prokaryotic abundances and the SOC accumulation rate suggest the periodic input of surficial sediments from the shallow region.The similar average TOC(0.31%–0.38%),TN(0.06%–0.07%)contents,and SOC compositions(terrestrial OC(11%–18%),marine phytoplanktonic OC(45%–53%),and microbial OC(32%–44%))of the three sites indicate that the lateral downslope transport has a significant mixing effect on the SOC composition.The output fluxes of the laterally transported SOC(0.44–0.56 g/(m^(2)·a)(in terms of OC))contributed approximately(47%–73%)of the total SOC input,and this proportion increased with water depth.The results of this study demonstrate the importance of lateral downslope transport in the spatial distribution and development of biomes. 展开更多
关键词 southern Yap Trench sedimentary organic carbon cycling lateral downslope transport diluting effect box model
下载PDF
A DYNAMIC BOX MODEL OF BIOACTIVE ELEMENTS IN THE SOUTHERN TAIWAN STRAIT 被引量:4
5
作者 洪华生 商少凌 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1994年第2期120-129,共10页
A dynamic box model was applied to study the characteristics of biogeochemical cycling of PO<sub>4</sub>-P,NO<sub>3</sub>-N,AOU,POC and PON in the southern Taiwan Strait region based on field d... A dynamic box model was applied to study the characteristics of biogeochemical cycling of PO<sub>4</sub>-P,NO<sub>3</sub>-N,AOU,POC and PON in the southern Taiwan Strait region based on field data of the"Minnan Taiwan Bank Fishing Ground Upwelling Ecosystem Study" during the period of Dec.1987-Nov.1988.According to the unique hydrological and topographical features of the region,six boxesand three layers were considered in the model.The variation rates and fluxes of elements induced by hor-izontal current,upwelling,by diffusion,sinking of particles and biogeochemical processes were estimatedrespectively.Results further confirmed that upwellings had important effects in this region.Thenearshore upwelling areas had net input fluxes of nutrients brought by upwelling water,also had high de-pletion rates of nutrients and production rates of particulate organic matter and dissolved oxygen.Theabnormal net production of nutrients in the middle layer(10-30m) indicated the important role of bacte-ria in this high production region. 展开更多
关键词 box model bioactive ELEMENTS PARTICULATE ORGANIC carbon FLUX UPWELLING
下载PDF
Black Box Modeling Method and Its Application in Refractories Techniques
6
作者 WANG Jiezeng YUAN Lin YE Yahong LI Penghai WANG Juntao 《China's Refractories》 CAS 2012年第4期1-6,共6页
Concept of black box, condition of modeling and control methods were introduced. Taking high purity silica brick as an example, the silica brick featured with high purity, low porosity, low true density and high stren... Concept of black box, condition of modeling and control methods were introduced. Taking high purity silica brick as an example, the silica brick featured with high purity, low porosity, low true density and high strength was developed through problem analysis, test design, modeling and optimization. Using information technology to upgrade refractories industry was discussed. 展开更多
关键词 black box modelING OPTIMIZATION TECHNIQUES REFRACTORIES
下载PDF
Inter-comparisons of VOC oxidation mechanisms based on box model:A focus on OH reactivity 被引量:3
7
作者 Xiaoyun Yang Bin Yuan +5 位作者 Zhe Peng Yuwen Peng Caihong Wu Suxia Yang Jin Li Min Shao 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2022年第4期286-296,共11页
Volatile organic compounds(VOCs)oxidation processes play a very important role in atmospheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understand... Volatile organic compounds(VOCs)oxidation processes play a very important role in atmospheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understanding of VOCs evolution during oxidation processes and evaluate the discrepancies of VOCs oxidation schemes among different mechanisms,we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms.We compared the total VOC reactivity evolution under high-NO_(x)xconditions for several sets of precursors,including n-pentane,toluene,ethene,isoprene and a mixture of 57 Photochemical Assessment Monitoring Stations(PAMS)species in a 0-D photochemical box model.Inter-comparison of total VOC reactivity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms,which are mainly attributed to the different lumping approaches for organic species.The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity.SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC reactivity.Evidences suggest that the performance in simulating secondary organic products,OH concentrations and NO_(x)concentrations are related to the OH reactivity discrepancies among various chemical mechanisms.Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments.The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms. 展开更多
关键词 VOCs box model Chemical mechanism Total VOC reactivity VOC oxidation
原文传递
Analysis of Data on Xanthan Fermentation in Stationary Phase Using Black Box and Metabolic Network Models 被引量:2
8
作者 马红武 赵学明 唐寅杰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1999年第4期321-325,共5页
The xanthan fermentation data in the stationary phase was analyzed using the black box and the metabolic network models. The data consistency is checked through the elemental balance in the black box model. In the met... The xanthan fermentation data in the stationary phase was analyzed using the black box and the metabolic network models. The data consistency is checked through the elemental balance in the black box model. In the metabolic network model, the metabolic flux distribution in the cell is calculated using the metabolic flux analysis method, then the maintenance coefficients is calculated. 展开更多
关键词 xanthan fermentation black box model metabolic flux analysis maintenance coefficients
下载PDF
Hydrodynamic Modeling with Grey-Box Method of A Foil-Like Underwater Vehicle 被引量:3
9
作者 LIU Xin-yu LI Yi-ping +1 位作者 WANG Ya-xing FENG Xi-sheng 《China Ocean Engineering》 SCIE EI CSCD 2017年第6期773-780,共8页
In this study, a dynamic modeling method for foil-like underwater vehicles is introduced and experimentally verified in different sea tests of the Hadal ARV. The dumping force of a foil-like underwater vehicle is sens... In this study, a dynamic modeling method for foil-like underwater vehicles is introduced and experimentally verified in different sea tests of the Hadal ARV. The dumping force of a foil-like underwater vehicle is sensitive to swing motion. Some foil-like underwater vehicles swing periodically when performing a free-fall dive task in experiments. Models using conventional modeling methods yield solutions with asymptotic stability, which cannot simulate the self-sustained swing motion. By improving the ridge regression optimization algorithm, a grey-box modeling method based on 378 viscous drag coefficients using the Taylor series expansion is proposed in this study. The method is optimized for over-fitting and convergence problems caused by large parameter matrices. Instead of the PMM test data, the unsteady computational fluid dynamics calculation results are used in modeling. The obtained model can better simulate the swing motion of the underwater vehicle. Simulation and experimental results show a good consistency in free-fall tests during sea trials, as well as a prediction of the dive speed in the swing state. 展开更多
关键词 unmanned underwater vehicle grey-box model HYDRODYNAMICS ridge regression CORRELATIONS
下载PDF
Effect of opening the Drake Passage on the oceanic general circulation:A box model study 被引量:2
10
作者 SHAO QiuLi CHEN XianYao HUANG RuiXin 《Science China Earth Sciences》 SCIE EI CAS 2013年第9期1588-1598,共11页
The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat e... The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat exchange between mid-and high latitudes in the Southern Ocean.After the opening of the DP,the Antarctic Circumpolar Current(ACC) forms and its associated strong temperature front blocks the heat transport from mid-latitudes to high latitudes.A simple box model is formulated,in which the effects of the wind stress(for the case of DP closed) and the thermal front(for the case of DP open) on the variability of Antarctic Bottom Water(AABW) and North Atlantic Deep Water(NADW) are explored.The sensitivity experiments demonstrate that:(1) When the DP is closed,the enhancement of the wind-driven gyre leads to the decline of AABW formation in the Southern Ocean and the increase of NADW formation in the North Atlantic.As a result,water in high latitudes of the Southern Ocean becomes warmer,so does the bottom water of global ocean.(2) When the DP is open,there is no formation of AABW until the intensity of thermal front along ACC exceeds a threshold value(it is 4.03℃ in our model).Before the formation of AABW,temperature in most of the oceans is higher than that after the formation of AABW,which usually leads to the cooling of high latitudes of the Southern Hemisphere and the bottom water in global ocean.When the strength of the thermal front is lower than the critical value,there is no AABW formation,and temperature in most of the oceans is slightly higher.These results demonstrate that during the opening of the DP,changes in wind stress and the formation of the thermal front in the Southern Ocean can substantially affect the formation of AABW and NADW,thus changing the state of meridional overturning circulation in the global ocean. 展开更多
关键词 Effect of opening the Drake Passage on the oceanic general circulation:A box model study
原文传递
Analysis of Gas Radiative Transfer Using Box Model and Its Comparison with Gray Band Approximation
11
作者 Yuying Liu Xinxin ZhangThermal Engineering Department, University of Science and Technology Beijing, Beijing 100083, China 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第1期82-88,共7页
On the basis of a wide range survey of various models or treatment methods for the calculation of radiative properties of gases, box model, which is similar to the gray band approximation of spectral band model, was a... On the basis of a wide range survey of various models or treatment methods for the calculation of radiative properties of gases, box model, which is similar to the gray band approximation of spectral band model, was applied to evaluate the gas properties in this paper. In order to compare the accuracy of box model with that of gray band approximation of spectral band models, a typical one-dimensional gas radiation problem was analyzed using discrete ordinate method. Comparing with the widely used gray band approximation of narrow band model or exponential wide band model, box model can well evaluate the radiation source term of the radiative problem. It also has the advantages of simplicity and easy to code, so it is practicable and useful for some complex engineering problems. 展开更多
关键词 gray band approximation spectral band model box model discrete ordinate method.
原文传递
Grey box modeling of supermarket refrigeration cabinets
12
作者 K.Leerbeck P.Bacher +1 位作者 C.Heerup H.Madsen 《Energy and AI》 2023年第1期63-70,共8页
Aiming to enable robust large-scale fault diagnostics and optimized control for supermarket refrigerationsystems, a data-driven grey box model for an evaporator and its surrounding cooling cabinet (or room) ispresente... Aiming to enable robust large-scale fault diagnostics and optimized control for supermarket refrigerationsystems, a data-driven grey box model for an evaporator and its surrounding cooling cabinet (or room) ispresented. It is a non-linear model with two states: the cabinet temperature and the refrigerant mass in theevaporator. To demonstrate its applicability, data with one-minute sampling resolution from ten evaporators ina supermarket in Otterup (Denmark) was used. The model parameters were estimated using a Kalman filter andthe maximum likelihood method. Since the dynamical properties of the cabinets constantly change as goodsare added and removed, the parameters were re-estimated for each night, over a period of approximately 2.5years. The model is validated through a statistical analysis of the residuals and the importance of the ongoingre-estimation of parameters is highlighted. Furthermore, the physical meaning of the estimated parameters isdiscussed and potential applications for characterization and classification of cabinets are demonstrated, byshowing how they can be differentiated as either open- or closed cabinets or rooms, using only the estimatedheat transfer coefficients and heat capacities. For a selected case it is shown that the estimated parametervalues are close to physics derived values, and that the accuracy measured by the standard errors of theestimates is approximately ±10% relative to the estimated values. The analysis demonstrates that the modelis robust, accurate and reliable in terms of estimating physically meaningful parameters and it is thereforeappropriate for large-scale implementation. 展开更多
关键词 Grey box modeling CO_(2) refrigeration systems Refrigeration cabinets and evaporators System identification CLASSIFICATION
原文传递
Subsystem model-based close-loop grey-box identification method for hydraulic stewart platform
13
作者 唐建林 董彦良 赵克定 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第2期107-112,共6页
In order to solve the problem of difficult modeling and identification caused by time-variable parameters,multiple inputs and outputs and unstable open loop,a subsystem model-based close-loop grey-box identification m... In order to solve the problem of difficult modeling and identification caused by time-variable parameters,multiple inputs and outputs and unstable open loop,a subsystem model-based close-loop grey-box identification method was put forward when consider the main coupling effects of hydraulic Stewart platform.Firstly,the whole system is divided into three TITO(Two Input Two Output) subsystems according to the characteristics of the pseudo-mass matrix,hence transfer function matrix model of the subsystem can also be found.Secondly,since the Stewart platform is unstable,the close-loop transfer model of the subsystem is derived under the proportional controllers.The inverse M serial is adopted as the identification signal to get the experimental data.All parameters of the subsystem are determined in close-loop indirect identification by PEM(Prediction Error Method).Finally,a case study validates the correctness and effectiveness of the subsystem model-based close-loop grey-box identification method for hydraulic Stewart platform. 展开更多
关键词 hydraulic Stewart platform pseudo-mass matrix prediction error method close-loop indirect identification grey-box model
下载PDF
Modelling Epidemiological Data Using Box-Jenkins Procedure 被引量:2
14
作者 Stanley Jere Edwin Moyo 《Open Journal of Statistics》 2016年第2期295-302,共8页
In this paper, the Box-Jenkins modelling procedure is used to determine an ARIMA model and go further to forecasting. We consider data of Malaria cases from Ministry of Health (Kabwe District)-Zambia for the period, 2... In this paper, the Box-Jenkins modelling procedure is used to determine an ARIMA model and go further to forecasting. We consider data of Malaria cases from Ministry of Health (Kabwe District)-Zambia for the period, 2009 to 2013 for age 1 to under 5 years. The model-building process involves three steps: tentative identification of a model from the ARIMA class, estimation of parameters in the identified model, and diagnostic checks. Results show that an appropriate model is simply an ARIMA (1, 0, 0) due to the fact that, the ACF has an exponential decay and the PACF has a spike at lag 1 which is an indication of the said model. The forecasted Malaria cases for January and February, 2014 are 220 and 265, respectively. 展开更多
关键词 box-Jenkins modeling Procedure ARIMA model Exponential Decay SPIKE
下载PDF
FURTHER PROBE OF COSMIC-RAY DOUBLE LEAKY BOX MODEL
15
作者 张力 喻传赞 《Chinese Science Bulletin》 SCIE EI CAS 1990年第17期1424-1429,共6页
In recent years, the measurements of cosmic-ray nuclei and electrons with higher accuracy have made it possible to study further the cosmic-ray propagation models. According to the current theories about cosmic-ray or... In recent years, the measurements of cosmic-ray nuclei and electrons with higher accuracy have made it possible to study further the cosmic-ray propagation models. According to the current theories about cosmic-ray origin, the energy spectra of nuclei and electrons are assumed to have the same shapes, i.e. q(E)=AE<sub>0</sub><sup>-γ</sup>, here A is a constant, E is the energy and γ<sub>0</sub> is the spectral index of source. However, the fittings to the data of nuclei and electrons in the single leaky box model give γ<sub>0p</sub>=2.0 for nuclei and γ<sub>0e</sub>=2.7 for electrons, respectively, which do not agree with the theories of cosmic-ray origin. 展开更多
关键词 COSMIC-RAYS PROPAGATION model leaky box model.
原文传递
大豆MADS-box基因功能研究进展
16
作者 姚晓琳 张晓芳 +4 位作者 王铮 郝俊莹 郑荣繁 张沿政 李帅 《植物遗传资源学报》 CAS CSCD 北大核心 2024年第6期909-918,共10页
MADS-box是植物体内一种重要的转录因子,其家族成员具有典型的MIKC结构、高度保守的N端MADS以及保守性较低的I域和C端。MADS-box基因广泛表达于植物的根、茎、叶、花、芽等组织部位,并参与调控花期、花器官发育、种子发育及非生物胁迫... MADS-box是植物体内一种重要的转录因子,其家族成员具有典型的MIKC结构、高度保守的N端MADS以及保守性较低的I域和C端。MADS-box基因广泛表达于植物的根、茎、叶、花、芽等组织部位,并参与调控花期、花器官发育、种子发育及非生物胁迫响应等过程。近年来的研究报道显示,不同MADS-box基因的表达模式不尽相同,其功能也存在较大差异。本文概述了大豆MADS-box基因家族的结构及分类,总结了大豆MADS-box基因家族花发育ABCDE模型中相关成员及SVP、SOC1、FLC等基因的研究进展。最后对大豆MADS-box的研究提出了展望,为今后进一步挖掘和利用该类转录因子基因进行大豆遗传改良和种质创新提供参考依据。 展开更多
关键词 大豆 MADS-box ABCDE模型 转录因子
下载PDF
Using Box-Jenkins Models to Forecast Mobile Cellular Subscription 被引量:3
17
作者 Ian Siluyele Stanley Jere 《Open Journal of Statistics》 2016年第2期303-309,共7页
In this paper, the Box-Jenkins modelling procedure is used to determine an ARIMA model and go further to forecasting. The mobile cellular subscription data for the study were taken from the administrative data submitt... In this paper, the Box-Jenkins modelling procedure is used to determine an ARIMA model and go further to forecasting. The mobile cellular subscription data for the study were taken from the administrative data submitted to the Zambia Information and Communications Technology Authority (ZICTA) as quarterly returns by all three mobile network operators Airtel Zambia, MTN Zambia and Zamtel. The time series of annual figures for mobile cellular subscription for all mobile network operators is from 2000 to 2014 and has a total of 15 observations. Results show that the ARIMA (1, 2, 1) is an adequate model which best fits the mobile cellular subscription time series and is therefore suitable for forecasting subscription. The model predicts a gradual rise in mobile cellular subscription in the next 5 years, culminating to about 9.0% cumulative increase in 2019. 展开更多
关键词 Mobile Cellular Subscription box-Jenkins Methodology ARIMA model Autocorrelation Function Partial Autocorrelation Function
下载PDF
A Novel Black Box Based Behavioral Model of Power Amplifier for WCDMA Applications
18
作者 Amandeep Singh Sappal Manjeet Singh Patterh Sanjay Sharma 《Communications and Network》 2010年第3期162-165,共4页
In this paper, Black Box approach is presented for behavioral modeling of a non linear power amplifier with memory effects. Large signal parameters of a Motorola LDMOS power amplifier driven by a WCDMA signal were ext... In this paper, Black Box approach is presented for behavioral modeling of a non linear power amplifier with memory effects. Large signal parameters of a Motorola LDMOS power amplifier driven by a WCDMA signal were extracted while taking into considerations the power amplifier’s bandwidth. The proposed model was validated based on the simulated data. Some validation results are presented both in the time and frequency domains, using WCDMA signal. 展开更多
关键词 BEHAVIORAL model BLACK box Power AMPLIFIERS
下载PDF
基于PSModel的海上风电场全电磁暂态建模与仿真
19
作者 崔森 郁舒雁 《电网技术》 EI CSCD 北大核心 2024年第1期262-271,共10页
开发有效的风机电磁暂态模型是进行海上风电并网研究的基础。根据不同生产厂家所提供的直驱风机模型,提出了一种基于厂家黑盒模型的直驱风机电磁暂态建模方法。利用厂家所提供的模型测试数据解析风机的故障响应特性,推导了不同厂家在电... 开发有效的风机电磁暂态模型是进行海上风电并网研究的基础。根据不同生产厂家所提供的直驱风机模型,提出了一种基于厂家黑盒模型的直驱风机电磁暂态建模方法。利用厂家所提供的模型测试数据解析风机的故障响应特性,推导了不同厂家在电压故障下有功和无功功率响应表达式,包括故障期间的穿越控制过程及不同过程间的暂态切换策略。提出了加权平均压降的风电场等值方法,采用自主研发的全电磁暂态仿真软件(power system model,PSModel)对我国广东某海上风电场进行全电磁暂态建模。根据稳态潮流及暂态特性结果验证了模型可通过系统测试,且有效实现了海上风电场的全电磁暂态建模,从而为该风场接入大电网后的安全稳定分析提供了研究基础。 展开更多
关键词 直驱风电机组 黑盒模型 海上风电场 PSmodel 故障穿越
下载PDF
An Econometric Analysis of Hospital Length of Stay for Cataract Operations in Japan by the Box-Cox Transformation Model and Hausman Tests: Evaluation of the 2010 Revision of the Medical Payment System
20
作者 Kazumitsu Nawata Koichi Kawabuchi 《Open Journal of Applied Sciences》 2015年第9期559-570,共12页
The Japanese medical costs for cataract treatments reached 270 billion yen in fiscal year 2012. Since the length of stay (LOS) in hospital is much longer than other major countries, controlling the medical costs by re... The Japanese medical costs for cataract treatments reached 270 billion yen in fiscal year 2012. Since the length of stay (LOS) in hospital is much longer than other major countries, controlling the medical costs by reducing LOS becomes an important issue in Japan. In this paper, we evaluated the effects of the 2010 revision of the Japanese medical payment system (DPC/PDPS) on LOS for cataract operations. The Box-Cox transformation model, Nawata’s estimators and Hausman tests were used in the analysis. To evaluate the effects, we analyzed a dataset obtained from 34 DPC hospitals (Hp1-34) where one-eye cataract operations were performed both before (April 2008-March 2010) and after (April 2010-March 2012) the 2010 revision and there were more than 500 patients. The dataset contained information from 32,593 patients. We did not admit the effect of the 2010 revision in this study, and there were large differences LOS among hospitals, even after removing the influences of factors such as patient characteristics and types of principal diseases. 展开更多
关键词 Diagnosis Procedure Combination (DPC) CATARACT Length of Stay (LOS) box-Cox TRANSFORMATION model
下载PDF
上一页 1 2 98 下一页 到第
使用帮助 返回顶部