基于粒子群算法的浮筒配置优化问题的研究

针对传统的验证法在解决浮筒配置问题中存在的计算量大、计算时间长、工作重复性强等缺点,提出了一种将浮筒纵向位置配置和浮筒充气量综合考虑、一体优化的方法。文章将各种合理性校验准则作为约束条件,通过逼近沉艇起浮瞬间和浮起后的平衡状态,来求取各对浮筒的纵向位置和充气量,将浮筒配置问题转换为一个多目标、多约束的最优化问题。在此基础上,根据粒子群优化算法的特点,提出了一种双向搜索策略,来求解浮筒配置优化问题。这种方法简单实用,计算时间短,无需人工干预,算法运行一次可获得多组配置方案供决策人员选择。算例表明用这种方法来解决浮筒配置问题是可行的、有效的。     

Optimization of fishing vessels using a Multi-Objective Genetic Algorithm

A fishing boat hull is used as an example of how hull form optimization can be accomplished using a Multi-Objective Genetic Algorithm (MOGA). The particular MOGA developed during this study allows automatic selection of a few Pareto Optimal results for examination by the designers while searching the complete Pareto Front. The optimization uses three performance indices for resistance, seakeeping and stability to modify the hull shape to obtain optimal hull offsets as well as optimal values for the principal parameters of length, beam and draft. The modification of the 148/1-B fishing boat hull, the parent hull form of the ?stanbul Technical University (?TÜ) series of fishing boats, is presented by first fixing the principal parameters and allowing the hull offsets to change, and secondly by simultaneously allowing variation of both the principal parameters and the hull offsets. Improvements in all three objectives were found. For further research the methodology can be modified to allow for the addition of other performance objectives, such as cost or specific mission objectives, as well as the use of enhanced performance prediction solvers. In addition, one or more hulls could be evaluated by experiment to validate the results of using this particular optimization approach.     

坛紫菜氨基酸提取工艺影响条件的优化与分析

以坛紫菜（Porphyra haitanensis）为实验材料,采用盐酸水解法和浸提法,以日立L-8900型高速全自动氨基酸分析仪为测定仪器,分别研究了坛紫菜总氨基酸（TAA）和游离氨基酸（FAA）在提取过程中各条件的不同水平对提取结果的影响.实验结果表明：（1）利用正交设计L9（34）对影响TAA提取的4个条件（藻体质量、稀释倍数、干燥温度、空白值）在3个水平上进行优化实验,藻体质量、稀释倍数对测定结果影响显著,干燥温度影响不显著;通过实验筛选出各条件的最佳水平为：藻体质量为0.050 0g,稀释3倍,干燥温度为60℃.（2）利用正交设计L16（45）对影响FAA测定的5个条件（藻体质量、提取液、提取温度、提取时间、空白值）在4个水平上进行优化实验,结果表明藻体质量、提取液、提取温度、提取时间的不同水平对测定结果均有显著影响,其中藻体质量对结果的影响最大;通过实验筛选出各条件的最佳水平为：藻体质量为0.010 0 g,提取液为去离子水,提取温度为60℃,提取时间为4 h.     

Vibrations of a rectangular orthotropic plate with a free edge: a comparison of analytical and numerical results

Transverse vibrations of a rectangular orthotropic plate with a free edge while the others are supported according to four different combinations of boundary conditions are considered in the present paper. The presence of a concentrated mass is also taken into account. In view of the difficulty of satisfying exactly the natural boundary conditions at the free edge, the fundamental frequency of vibration is determined by means of the optimized Rayleigh-Ritz method and a pseudo-Fourier expansion which contains, in its argument, the optimization parameters γ_i. The results are in excellent agreement with those obtained by means of a finite element algorithmic procedure.     

海水硅酸盐现场自动监测技术化学工艺优化研究

阐述了硅酸盐测量时试剂的不稳定性，介绍了还原剂配出时间与吸光值之间的关系、化学反应时间的确定及温度对化学反应的影响和盐度效应问题，给出了硅酸盐现场自动化学分析工艺优化流程图。     

极化SAR目标相对最优极化研究

目标相对最优极化就是选取一种极化状态,使得研究目标和背景地物的接收功率对比达到最大。通过讨论了目标相对最优极化问题,提出了改进的模型和解算方法,利用实际数据对其模型和方法进行了实验,验证了其有效性和正确性。     

A mixed continuous and discrete nonlinear constrained algorithm for optimizing ship hull structural design

A nonlinear search algorithm for optimizing constrained design of ship structures is presented. The decision variables can be continuous or discrete and the constraints can be homogeneous or inequality nonlinear functions of those variables. The algorithm does not use gradients; therefore, it can work with non-systematized functions such as tables or another class of design routine. It was tested in the structural design of a Patrol Boat and has proved to be a powerful tool decreasing the time expended in preliminary design when it is done by the conventional spiral approach.     

黄河三角洲滩涂区海堤护岸结构方案优化实证研究

海堤护岸是抵御和减轻风暴潮灾害的根本措施,是从根本上消除风暴潮对沿岸人民生命财产安全威胁的最有效措施之一。黄河三角洲沿海滩涂广阔平坦,多为沙质和淤泥质,沟壑交错,海堤护岸的建设量大面广,所以对区域内海堤护岸的建设方案进行比较优化,更显得十分必要。文章通过具体的工程案例,阐述了建于黄河三角洲滩涂区的海堤护岸结构方案的比选与优化步骤与方法,这无疑对建于滨海滩涂区的海堤护岸的方案优化具有直接的参考与借鉴意义。     

对转压气机三维掠动叶优化设计

为探索三维掠动叶降低对转压气机二次流损失的潜力,进一步提高对转压气机气动性能,基于近似函数与遗传算法,针对某对转压气机双排转子在整机环境下进行三维掠动叶优化设计,并对优化前后流场进行对比分析。优化成功的得到了双排“S”形掠动叶,结果表明:三维掠动叶有效改善了双排动叶吸力面径向二次流,减小了吸力面低速区,提高了对转压气机性能,优化工况点整机效率提高0.6%,全工况范围内效率均有所提高;三维掠动叶提高对转压气机效率的根本原因是其对径向负荷分配的重新调整,将叶展下方流动较差区域负荷移至叶展上方,改善流场的同时保证对转压气机负荷不变。      

艏艉线型优化对船舶阻力性能的影响

为提高母型船阻力性能,以船体阻力性能为优化对象,基于改造母型船法,研究船舶球鼻艏以及船尾线型的改变对船舶阻力性能的影响.采用高度集成化的Tribon系统、可视化绘图软件Auto CAD及CFD(Computational Fluid Dynamics)通用前处理软件ICEM联合建模的方法来建立船体模型.通过模拟计算结果与实验值的对比分析,验证CFD技术在船舶阻力性能预报中的合理性和有效性.通过对比3种不同球鼻艏时的船体阻力得知:从阻力性能方面考虑,对于低速丰满型船舶选用普通型球鼻艏以及中高速船舶采用上翘型球鼻艏均可以获取较好地减阻效果.同时比较不同航速下尾部线型对船体总阻力的影响表明,选优后的方形尾在相同的航速下阻力低、消耗的功率小、形状效应小、黏压阻力和摩擦阻力也相对较小.     

四种重金属对刺参幼参的急性致毒效应

采用静水试验法,在水温18.5℃~20℃的条件下,用Cu2 ,Zn2 ,Cd2 和Cr6 四种重金属对刺参幼参进行了单一急性毒性试验。结果表明:Cu2 对刺参幼参的24h,48h,72h和96hLC50分别为0.299,0.176,0.133和0.120mg/L;Zn2 的24h,48h,72h和96hLC50分别为6.700,3.624,2.577和1.951mg/L;Cd2 的24h,48h和72hLC50分别为4.246,2.588和2.137mg/L;Cr6 的24h,48h和72hLC50分别为31.974,7.499和3.808mg/L;Cu2 ,Zn2 ,Cd2 和Cr6 对刺参幼参的安全浓度分别为0.018,0.362,0.259和0.750mg/L。四种重金属对刺参幼参的毒性大小依次为Cu2 >Cd2 >Zn2 >Cr6 。     

海洋工程结构的多目标模糊优化设计

本文从模糊综合评判的角度出发，研究了海洋工程结构的多目标优化设计方法。运用模糊层次分析法来确定各追逐目标的重要性因子；通过模糊变换求得方案的模糊评判；并用理想评判集的模糊识别法确定设计方案的优劣。从而进行结构的优化设计。文章还给出了海洋平台桩腿结构的模糊优化设计实例。     

Optimization design on the riser system of next generation subsea production system with the assistance of DOE and surrogate model techniques

The Next Generation Subsea Production System (NextGen SPS) is a new concept for petroleum development in ultra-deep water (UDW) areas. It can improve the structural performance of riser as well as provide several operational benefits to subsurface well completion (SWC) equipment. The design of NextGen SPS’s riser system which includes rigid riser and flexible jumper—like the free standing hybrid riser (FSHR), is a very important issue for the definition of NextGen SPS. This paper details an optimization design on the NextGen SPS’s riser system, with the assistance of the design of experiments (DOE) and surrogate model techniques. The optimization model pertaining to riser system is formulated firstly. The DOE is a statistical technique that guides a sensitive study on the behavior of the riser system before the optimization analysis. Structural responses are obtained by the fully coupled methodology. Through such a preliminary study, the effective contribution of each design variable at the riser performance will be known and some general conclusive remarks will be obtained. Based on the DOE results, design variables are screened to improve the efficiency of optimization process. Particle swarm optimization (PSO) method is employed to conduct the optimization analysis. In this analysis, surrogate models, which are developed by back propagation neural network (BPNN), replace the time consuming dynamic analysis to predict structural responses. Latin hypercube sampling (LHS) method is adopted to generate training sample and testing sample for the BPNN. NextGen SPS that operates at a depth of 3000 m is used as the case for this investigation. The efficiency of optimization design is improved by DOE and surrogate techniques, and a reduction of approximately 46% for the riser system cost is achieved. The obtained conclusions have applicability in reference to the engineering design of FSHR and the study procedure will provide reference for study on other new structure concept.     

综合空间相关性和区域分异性方法的上海海洋环境监测站位优化

综合无机氮和活性磷酸盐的海水水质类别现状进行空间分区,拟合无机氮和活性磷酸盐全局半变异函数和局部半变异函数。通过留一交叉检验方法确定统计推断方法,无机氮采用分层克里金插值方法,使得平均绝对误差和误差方差最小;活性磷酸盐采用普通克里金插值方法,使得平均绝对误差和误差方差最小。原则上调整现有站位数的10%,综合考虑对无机氮和活性磷酸盐插值标准差的变化影响,以及对不同水质类别面积的影响,确定去掉冗余的7个历史站位。7个站位均分布在劣四类水区域的长江口南支、北支、和杭州湾北部近岸区域,这些区域站点密集,水体中各要素含量变化不大,水团混合较均匀。优化删减掉的7个站位调整到三类和四类水质分区中,或者无限制区域的优化调整,发现调整优化的站位主要分布在水质类别变化过渡的区域,因此,不同水质类别的分界带以及海域边界处是站位调整优化的关键区域。     

VBF水下传感器网络路由协议的路径优化与模拟

针对水下传感器网络节点的移动性,以基本VBF(Vector-Based Forwarding Protocol)路由协议为基础,提出了1种适用于水下移动传感器节点的路径优化算法.为了验证此路径优化算法的有效性,分别对基本VBF算法和改进的VBF算法进行了3个模拟实验;从数据包接收成功率和网络负载两方面分析比较了实验模拟结果.比较结果可以看出:文中提出的路径优化的VBF路由协议的数据包成功接收率要优于VBF路由协议,降低了网络负载,并且该优化算法实现简单,不需要增加额外的网络延迟时间.     

Tracing dissolved organic matter cycling in the eastern boundary of the temperate North Atlantic using absorption and fluorescence spectroscopy

Apparent oxygen utilization (AOU), dissolved organic carbon (DOC), coloured dissolved organic matter (CDOM) absorption spectra, and CDOM fluorescence characteristic of aromatic amino acids (excitation/emission 280 nm/320 nm; F(280/320)) and marine-humic like substances (320 nm/410 nm; F(320/410)) were measured in full depth during a cruise in the temperate Eastern North Atlantic (ENA). An optimum multi-parameter (OMP) inverse method was run to calculate water mass proportion-weighted average (archetypal) concentrations of these chemical parameters for all water masses and samples. Archetypal concentrations retain the variability due to water mass mixing and basin scale mineralization from the water mass formation sites to the study area. Conversely, the difference between measured and archetypal concentrations, retain the variability due to dissimilarities in mineralization processes within the study area. Our analysis indicates that DOC supported 26±3% of the AOU in the dark temperate ENA and that basin scale processes occurring at and from the formation area of the water masses explained 63% of the total DOC variability. Our data also suggests that DOC remineralized at the basin scale was of lower molecular weight, and with a lower proportion of fluorescent aromatic amino acids than found within the study area. The relationship between the absorption coefficient at 254 nm (a_CDOM(254)) and AOU indicates that a_CDOM(254) was consumed during organic matter remineralization in the dark ocean, with 55% of the variability being explained by basin scale processes. The relationships of F(320/410) with AOU and DOC confirmed that marine humic-like substances are produced by microbial degradation processes, at a rate of 6.1±0.9×10⁻³ mg equivalents of QS mol AOU⁻¹. Our results also indicate that basin-scale remineralization processes account for 85% of the total variability of F(320/410), emphasizing that large scale processes control the formation of humic-like substance in the dark ENA.     

海洋中β-二甲基巯基丙酸内盐降解过程的研究进展

二甲基硫(DMS)是海水中一种最重要的、含量最丰富的还原态挥发性生源有机硫化物,前体β-二甲基巯基丙酸内盐(DMSP)的降解过程受各种因素影响。其中主要包括温度、DMSP的浓度、氧气、盐度、酸度、颗粒粒度、藻类生长期、季节变化、氧化压力、抑制剂等。它们均与DMSP降解速率呈一定的函数关系,并对DMSP的降解产物产生影响。藻类是DMSP的主要来源,因此着重讨论了温度、盐度、酸度等对不同浮游植物细胞内DMSP与DMS生物生产和转化过程的影响。结合海洋硫循环的研究现状和海洋化学发展的趋势,探究了用颗粒态DMSP与Chla的比率来量化碳和硫通量的方法及DMSP裂解酶活性的检验技术。大气中CO2压力持续增加导致的海洋酸化对藻类中DMSP降解过程的影响也是进一步研究的重点。     

Ballast water management in Canada: A historical perspective and implications for the future

Non-indigenous species (NIS) can create significant risks when introduced to foreign ecosystems. One of the many vectors facilitating the global transport of NIS is ballast water, and as commercial shipping increases so does the threat of ballast water-mediated introductions. Despite Canadian regulations, consistent with international guidelines put forth by the International Maritime Organization in the early 1990s, ballast water remains a potential vector for the introduction of many NIS to Canadian marine ecosystems: there have been no new introductions in the Laurentian Great Lakes Region since 2006, yet marine ecosystems continue to see the introduction and establishment of NIS. This paper details and analyzes the development of Canadian ballast water management (BWM), in the context of marine ecosystems, and identifies issues therein. BWM in Canada has a number of management gaps that have persisted since large-scale BWM began in the late 1980s. These include BWM exemptions for vessels not exiting the North American continental shelf, and limitations of effectiveness of mid-ocean exchange as the predominant management method in marine ecosystems. In addition, ballast water regulations for the Canadian Arctic may require additional consideration as the Arctic will likely continue to see an increase in both warming and commercial shipping in the future, thereby increasing the potential risk of NIS. In order to adequately protect all Canadian marine ecosystems, it is recommended that the current BWM regime: fill gaps in management to help prevent further introduction and spread of NIS; focus equally on both marine and freshwater regions, and; look to other aggressive BWM strategies such as those being developed by the state of California.     

Sources and implications of particulate organic matter from a small tropical river——Zuari River,India

Transitional ecosystems,estuaries and the coastal seas,are distinctively affected by natural and anthropogenic factors.Organic matter(OM)originating from terrestrial sources is exported by rivers and forms a key component of the global biogeochemical cycles.Most previous studies focused on the bulk biochemical and anthropogenic aspects affecting these ecosystems.In the present study,we examined the sources and fate of OM entrained within suspended particulate matter(SPM)of the Zuari River and its estuary,west coast of India.Besides using amino acid(AA)enantiomers(L-and D-forms)as biomarkers,other bulk biochemical parameters viz.particulate organic carbon(POC),δ13C,particulate nitrogen(PN),δ15N and chlorophyll a were analyzed.Surprisingly no significant temporal variations were observed in the parameters analyzed;nonetheless,salinity,POC,δ13C,PN,δ15N,glutamic acid,serine,alanine,tyrosine,leucine and D-aspartic acid exhibited significant spatial variability suggesting source differentiation.The POC content displayed weak temporal variability with low values observed during the post-monsoon season attributed to inputs from mixed sources.Estuarine samples were less depleted than the riverine samples suggesting contributions from marine plankton in addition to contributions from river plankton and terrestrial C3 plants detritus.Labile OM was observed during the monsoon and post-monsoon seasons in the estuarine region.More degraded OM was noticed during the pre-monsoon season.Principal component analysis was used to ascertain the sources and factors influencing OM.Principally five factors were extracted explaining 84.52%of the total variance.The first component accounted for 27.10%of the variance suggesting the dominance of tidal influence whereas,the second component accounted for heterotrophic bacteria and their remnants associated with the particulate matter,contributing primarily to the AA pool.Based on this study we ascertained the role of the estuarine turbidity maximum(ETM)controlling the sources of POM and its implications to small tropical rivers.Thus,changes in temporal and regional settings are more likely to affect the natural biogeochemical cycles of small tropical rivers.