Design and reliability analysis of DP-3 dynamic positioning control architecture     

王芳  万磊  姜大鹏  徐玉如 《中国海洋工程》2011,25(4):709-720

As the exploration and exploitation of oil and gas proliferate throughout deepwater area,the requirements on the reliability of dynamic positioning system become increasingly stringent.The control objective ensuring safety operation at deep water will not be met by a single controller for dynamic positioning.In order to increase the availability and reliability of dynamic positioning control system,the triple redundancy hardware and software control architectures were designed and developed according to the safe specifications of DP-3 classification notation for dynamically positioned ships and rigs.The hardware redundant configuration takes the form of triple-redundant hot standby configuration including three identical operator stations and three real-time control computers which connect each other through dual networks.The function of motion control and redundancy management of control computers were implemented by software on the real-time operating system VxWorks.The software realization of task loose synchronization,majority voting and fault detection were presented in details.A hierarchical software architecture was planed during the development of software,consisting of application layer,real-time layer and physical layer.The behavior of the DP-3 dynamic positioning control system was modeled by a Markov model to analyze its reliability.The effects of variation in parameters on the reliability measures were investigated.The time domain dynamic simulation was carried out on a deepwater drilling rig to prove the feasibility of the proposed control architecture.  相似文献   

近50年来环境变化对巢湖硅藻组合演替的影响   总被引：4，自引：3，他引：1  

陈旭  羊向东  董旭辉  刘恩峰 《湖泊科学》2011,23(5):665-672

湖泊生态系统往往受营养、水文和气候等诸多环境因子的影响.区分不同环境因子的影响是揭示湖泊生态环境演化机制的关键.本文基于巢湖岩芯210Pb和137Cs测年、硅藻、地球化学指标和粒度分析结果以及流域水文、气候、人口和农业资料,利用冗余分析,定量区分1950年来营养、水文和气侯对硅藻组合演替的影响.1978年前硅藻组合中A...  相似文献   

MSAS基带信号处理关键技术     

刘文焘  谢金石 《时间频率学报》2009,32(2):129-133

给出了日本MSAS（多功能卫星增强系统）基带信号处理各项关键技术的算法原理,并对2006年在成都高楼上采集的MSAS卫星信号数据通过软件进行了基带信号处理,验证了各关键技术算法原理的正确性。另外,提出对GPS接收机增加1个MSAS通道以便提高我国GPS卫星导航接收机的定位精度和进一步增强GPS卫星导航完好性监测。  相似文献   

带有驱动器冗余的欠驱动船舶的自适应容错控制     

黄江帅  胡睿 《南京气象学院学报》2018,10(2):138-145

在本文中,一种非线性自适应控制容错策略的开发使得具有推力器冗余的欠驱动船舶可以遵循预定的路径行驶,尽管存在未知的系统参数以及由波浪、风和洋流引起的环境干扰.在设计和分析中涉及的技术包括使用反步法、参数投影技术和横向函数.结果表明,本文所提出的控制器,参考路径可以用任意小的跟踪误差进行全局跟踪.仿真结果证明了该控制器的有效性.  相似文献   

长湖浮游植物功能群特征及其与环境因子的关系   总被引：2，自引：0，他引：2  

祁梅  吴嘉伟  龚森森  柴毅  罗静波  谭凤霞  杨军  杨德国  何勇凤 《海洋与湖沼》2020,51(1):75-84

为查明长湖浮游植物功能群特征及其与环境因子的关系,于2015年4月至2016年1月开展了四个季度的调查分析,并运用冗余分析法(redundancy analysis,RDA)分析了浮游植物优势功能群与环境因子的关系。结果显示:本次调查共鉴定出26个浮游植物功能群,其中富营养化水体代表性功能群13个,优势功能群16个,其中功能群B、D、J、Lo、MP、W_1和X_1 (表1)为四季共有优势功能群。优势功能群的丰度和生物量均为夏季最高,春季其次。以最大相对丰度超过50%为评价指标,优势功能群的季节演替规律为X_1/X_2/B (春)→X_1(夏)→MP/X_1/B(秋)→D/X_1(冬),其中典型浅水富营养化水体代表功能群X_1的最大相对丰度和出现率均较高。冗余分析(RDA)表明,富营养化水体代表性功能群F、K、Lo、Lr、W_1和X_2在不同季节与总氮(TN)、磷酸盐(PO_4~(3-)-P)、溶解氧(DO)以及水温(WT)表现出不同程度的正相关性,水温(WT)和透明度(WD)是春季的主要环境限制因子,冬季X_1、D和J这三个优势功能群与各环境因子的相关性都很低。本次研究表明长湖整体处于中度富营养-富营养化状态,局部水域达到重度富营养化,这与运用其他指示生物对长湖的水质评价结果基本一致。  相似文献   

象山港海洋牧场示范区浮游植物的群落特征及其与环境因子的关系   总被引：1，自引：0，他引：1  

刘懂  陈晨  王莉  焦海峰  孙元  王一农  尤仲杰 《海洋与湖沼》2016,47(5):1024-1032

根据2014年4月至2015年1月于象山港海洋牧场示范区和对照区四季的浮游植物及同步的环境调查数据,对浮游植物的群落特征进行研究,并应用冗余分析(RDA)研究了该海域环境因子对浮游植物群落结构的影响。共鉴定出浮游植物95种,隶属于7门59属,主要由硅藻(64种)、绿藻(10种)和甲藻(9种)组成。优势种主要有琼氏圆筛藻(Coscinodiscus jonesianus)、太阳漂流藻(Planktoniella sol)和星脐圆筛藻(C.asteromphalus),且存在明显的季节演替现象。双因素分析结果表明:季节间,浮游植物丰度、多样性指数(Shannon-Wiener多样性、Pielou均匀度和Margalef丰富度)和环境因子(水温、盐度、p H、DO、NO_3-N、NO_2-N、NH_4-N、PO_4-P和Si O_3-Si)均存在极显著差异(P0.01),秋、春季全区丰度(121.59和79.39×10~4个/m~3)显著高于冬、夏季(13.05和7.05×10~4个/m~3),多样性指数均表现为冬夏秋春季;区域间,丰度、多样性指数和环境因子均无显著性差异(P0.05),示范区浮游植物丰度和多样性指数的四季均值都高于对照区。相似性聚类分析、多维尺度分析(n MDS)结果表明,浮游植物群落组成季节性差异显著,区域差异不显著。表明示范区的建设对浮游植物的生长有一定的积极作用,但效果不显著。RDA分析结果表明,盐度、温度、营养盐(NO_3-N、PO_4-P和Si O_3-Si)和DO是影响浮游植物群落结构的主要因子,各种浮游植物对环境因子的响应机制有所不同。  相似文献   

Design and implementation of a triple-redundant dynamic positioning control system for deepwater drilling rigs     

《Applied Ocean Research》2016

Triple-redundant control architecture of the main control station is proposed for dynamic positioning (DP) system from a practical point of view according to the International Maritime Organization's (IMO) DP Class 3 notation. To improve the single fault tolerance, both operator station systems and real-time control computer systems are designed with triple modular redundancy. Hierarchical software layers of the triple-redundant control architecture are implemented based on the different real-time response requirements of the layers. Input and output voting are incorporated to the positioning task to detect and isolate faults in the sensors and in the control system. Hard-in-the-loop (HIL) testing system together with model-scale tests are conducted to verify the proposed triple-redundant control architecture. The feasibility and fault-tolerant capability of the triple-redundant hardware and software architecture both in HIL and model tests are demonstrated.  相似文献   

BOOK REVIEWS     

《The Professional geographer》1987,39(1):94-129

Book Reviewed in this article: The Rice Economy of Asia . Randolph Barker and Robert W. Herdt with Beth Rose. Using Microcomputers: A Guidebook for Writers, Teachers, and Researchers in the Social Sciences . Blaine A. Erie—the Lake that Survived . Noel M. Burns. Geology and Society . Donald R. Coates. Caves and Karst of Kentucky . Percy H. Dougherty, ed. Altered Harvest: Agriculture, Genetics, and the Fate of the World's Food Supply . Jack Doyle. The Middle East and North Africa, A Political Geography . Alasdair Drysdale and Gerald H. Blake. Clamor at the Gates. The New American Immigration . Nathan Glazer, ed. Development and the Landowner: An analysis of the British experience . Robin Goodchild and Richard Munton. Discovering Landscape in England and Wales . Andrew Goudie and Rita Gardner. The Modern Plantation in the Third World . Edgar Graham and Ingrid Floering. Social Relations and Spatial Structures . Derek Gregory and John Urry, eds. The World Food Problem 1950–1980 . David Grigg. Costa Rica: A Geographical Interpretation in Historical Perspective . Carolyn Hall. The Urbanization of Capital: Studies in the History and Theory of Capitalist Urbanization . David Harvey Consciousness and the Urban Experience: Studies in the History and Theory of Capitalist Urbanization . David Harvey. Reviving Main Street . Deryck Holdsworth, ed. Rural Roads and Poverty Alleviation . John Howe and Peter Richards, eds. Uneven Development in Southern Europe: Studies of Accumulation, Class, Migration and the State . Ray Hudson and Jim Lewis, eds. Karst Geomorphology . J. N. Jennings. The Geomorphology of North-west England . R. H. Johnson, ed. Climate Impact Assessment: Studies of the Interaction of Climate and Society . Robert Kates, Jesse Ausubel, Mimi Berberian, eds. Public Service Provision and Urban Development . Andrew Kirby, Paul Knox, and Steven Pinch, ed. State and Market: The Politics of the Public and the Private . Jan-Erik Lane, ed. Living Cities . Twentieth Century Fund Task Force on Urban Preservation Policies. World Climatic Systems . John G. Lockwood. Urban Ethnicity in the United States. New Immigrants and Old Minorities . Lionel Maldonaldo and Joan Moore, eds. Culture and Conservation: The Human Dimension in Environmental Planning . Jeffrey A. McNeely and David Pitt, eds. The Andean Past. Land, Societies, and Conflicts . Magnus Mörner. Gaia: An Atlas of Planet Management . Norman Myers, ed. Progress in Industrial Geography . Michael Pacione, ed. Progress in Political Geography . Michael Pacione, ed. Rivers and Landscape . Geoff Petts and Ian Foster. Urbanization and Planning in the 3rd World: Spatial Perceptions and Public Participation . Robert B. Potter. One Island, Two Nations? A Political Geographical Analysis of the National Conflict in Ireland . D. G. Pringle. Circulation in Third World Countries . R. Mansell Prothero and Murray Chapman. The Ozarks Outdoors: A Guide for Fishermen, Hunters, and Tourists . Milton D. Rafferty. Suburban Burglary: A Time and a Place for Everything . George Rengert and John Wasilchick. Geomorphology and Soils . K.S. Richards, R.R. Arnett, and S. Ellis, eds. The Homes and Homeless of Post-War Britain . Frederick Shaw. Indochinese Refugees in America . Paul J. Strand and Woodrow Jones, Jr. Wild Horses and Sacred Cows . Richard Symanski. Forever Wild: Environmental Aesthetics and the Adirondack Forest Preserve . Philip G. Terrie. The Regional Economic Impact of Technological Change . A.T. Thwaites and R.P. Oakey, eds. The Good Life . Yi-Fu Tuan.  相似文献   

土地利用结构及其驱动因子的统计分析——以榆林地区为例   总被引：7，自引：0，他引：7  

张胆 《地理科学进展》1997,16(4):19-26

本文采用了典型相关分析这一经典的数理统计方法，对榆林地区土地利用结构的驱动因子进行了统计分析。通过大型社会科学统计软件包SPSS操作运行，并对统计结果进行专业分析，定量诊断出各驱动因子对该区土地利用结构分布贡献作用的大小。同时运用典型相关系数和冗余度分析，对诊断结果进行了检验。  相似文献   

Late-glacial pollen and diatom changes in response to two different environmental perturbations: volcanic eruption and Younger Dryas cooling   总被引：1，自引：0，他引：1  

A. F. Lotter  H. J. B. Birks  B. Zolitschka 《Journal of Paleolimnology》1995,14(1):23-47

A high-resolution pollen and diatom stratigraphy has been studied from late-glacial annually laminated sediments of Holzmaar (425 m a.s.l., Germany). The sediment sequence studied comprises 475 varves and includes two environmental perturbations of different type and duration: the short, abrupt deposition of the late Allerød tephra layer of the Laacher See volcano (LST, 11 000 yr B.P.), and the more gradual onset of the 'Younger Dryas climatic cooling.Numerical analyses involving (partial) redundancy analyses in connection with Monte Carlo permutation tests suggest that the deposition of 78 mm of Laacher See Tephra had a statistically significant effect on the pollen stratigraphy (percentage and accumulation rates), most probably because of the proximity of the site to the volcano. The diatom accumulation rates also show a statistically significant change, whereas the diatom percentage data do not change significantly. The between-sample rates-of-change in both biostratigraphies are higher at and just after the LST event than at the transition to the Younger Dryas biozone. Sequence splitting of pollen and diatom accumulation rate data also shows a clustering of significant splits at the LST event. A close correlation between changes in the pollen and diatom percentage data for the investigated time-interval suggests a common underlying climatic signal, whereas the accumulation rates of both biostratigraphies behave more individualistically and show more short-term variability due, in part, to the inherent noise in the two data sets. Variance partitioning shows that the local pollen and diatom assemblage zones explain much of the variance in the data-sets. Statistical modelling using redundancy analysis shows that the changes in the diatom assemblages are best predicted by the Younger Dryas biozone and the main changes in the pollen stratigraphy (as represented by the first PCA axis of the pollen data).The results suggest that the biostratigraphies studied at Holzmaar reflect generally stable systems which were disturbed by the deposition of the Laacher See Tephra. After a phase of recovery both systems again reached a new phase of stability prior to the long-term Younger Dryas climatic deterioration that perturbed the assemblages again. The very close and statistically significant parallelism between the major stratigraphical patterns in the pollen and diatom percentage data highlights the responses of the two biological systems to environmental perturbations at different temporal scales.  相似文献