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1.
考虑送箱集卡多码头调度的低碳、高效化要求,及为解决集卡不规律到达导致码头拥挤问题而提出的集卡预约集港机制,以单一外堆场调用送箱集卡数量最小及多集装箱码头调度方案碳排放总量最小为目标,构建了单堆场多码头送箱集卡调度模型.设计了改进的蚁群算法对该模型进行求解,得到按时间段划分的港外堆场多码头集卡低碳送箱方案,通过算例验证了所构建模型和算法的有效性.结果表明,考虑碳排放和预约机制的送箱集卡多码头调度方案所需集卡数量少,工作时间短,兼顾了集装箱码头集卡送箱作业低碳和高效的要求.  相似文献   

2.
研究集装箱码头集卡拥堵收费问题,目的是减少集卡排队等待时间,以及由集卡排队引起的污染排放.为确定最优的拥堵费率,建立了集卡拥堵收费的双层规划模型.模型考虑了码头运营商、集卡司机和政府管理者之间的博弈关系.在上层模型中,码头运营商以总排队费用最低为目标;下层是用户均衡模型,集卡司机以广义费用最低为目标选择到达时段,通过上下层模型间的反馈决定最优的拥堵收费方案.为求解模型,设计基于文化基因启发式(MH)算法和逐点固定流体近似(PSFFA)算法的求解方法,利用MH算法搜索最优收费方案,利用PSFFA算法计算排队时间.最后,应用算例对模型和算法的有效性进行验证.结果表明,拥堵收费可以有效地减少集卡排队时间,所设计的模型考虑了集卡收费的影响因素,以及码头运营商和集卡司机等主体之间的利益关系,为缓解码头集卡拥堵提供了一种有效的方法.  相似文献   

3.
岸桥与集卡是集装箱码头的重要资源。为了提高码头的装卸效率,针对集装箱码头岸桥和集卡的集成调度问题,以完工时间最小为优化目标,考虑集装箱之间优先关系和岸桥安全边际的实际约束,建立混合整数线性规划模型,利用改进粒子群算法(IPSO)对模型进行求解,制定了粒子编码和解码规则,设计了一种新的速度更新策略来改进解的质量。实验表明,将改进算法的结果与优化软件CPLEX所求得的最优解比较,IPSO算法求得12组数值算例的平均偏差为0.582%,且CPLEX计算时间的跨度随着计算规模的扩大从2.92 s到1 h,而IPSO的求解时间控制在50 s之内,并得到最优解,证明了该模型和算法可以快速有效地解决岸桥与集卡的集成调度问题。  相似文献   

4.
为解决岸桥同贝同步装卸时多环节作业协调问题,加速集装箱在码头内部的周转,研究基于岸桥同贝同步装卸作业的岸桥与集卡联合调度问题.以船舶装卸完工时间最短为目标,建立岸桥与集卡联合调度优化模型,优化岸桥与集卡的任务分配及作业序列.岸桥同贝同步装卸增加了集卡作业环节,不同于传统作业时多阶段混合流水车间问题,其模型更加复杂,求解更加困难.针对大规模问题,设计了启发式算法进行求解,并将求解结果与下界值进行对比分析.结果表明,该启发式算法能有效提高岸桥与集卡联合调度模型的求解速度,有助于提高岸桥同贝同步装卸作业效率,为码头实际作业提供依据.  相似文献   

5.
集装箱码头作为连接水陆两方的集装箱运输枢纽,在物流环节中起着重要作用.集装箱码头的装卸作业过程可以看成一个由岸桥、集卡、场桥组成的三阶段混合流水车间调度系统.为了提高集装箱码头的装卸作业效率、缩短船舶的靠泊时间,本文根据混合流水车间调度策略(HFSS),建立了以最小完成时间为目标函数的三阶段集成调度模型.求解过程中将集卡的因素考虑进去,使用基于改进的johnson法则的启发式算法来求解该模型.最后与遗传算法求解结果进行对比,发现在相同条件下,基于改进的Johnson规则的启发式算法相比于传统的遗传算法得到的结果更优,得到的最优解距离下界只有4.1%的差距.  相似文献   

6.
岸桥分配与集卡调度是相互联系相互影响的问题,如果要提高码头装卸效率,就必须协调好两者的调度关系。针对集装箱码头岸桥和集卡的协同调度问题,以使进口箱和出口箱的总完工时间最短为目的,考虑了集卡路径约束和岸桥实际操作情况等实际约束,构建了边装边卸的混合整数规划模型。由于模型比较复杂,因此采用了分层方法来实现两种设备的协调调度,并用改进的遗传算法来求解模型。实验表明,通过将改进算法的结果与标准化软件CPLEX所求得的最优解或下界比较,算法求得6组最优解且剩余算例平均偏差小于5%;在求解时间方面,随着岸桥、集卡和集装箱数量的增加,CPLEX求解时间跨度由1 s到1 h快速增长,而改进算法求解却仅仅需要几十秒,因此说明改进的算法可以快速有效地解决岸桥和集卡的协同调度问题。  相似文献   

7.
集装箱码头岸边装卸桥同贝同步装卸船模式下,岸桥装卸作业序列决策和集卡调度协同优化是保障同步装卸率的关键,属NP难问题。考虑集卡和岸桥作业之间的紧密衔接、堆场翻箱影响、船舶舱盖等空间约束,构建以岸桥装卸总次数及堆场翻箱次数最小化、岸桥最大完工时间最小化、集卡等待时间最小化为目标的岸桥装卸序列决策与集卡调度联合优化数学模型。设计改进遗传算法-改进非支配排序多目标遗传算法(IGA-INSGA-Ⅱ)两阶段算法,利用IGA求解船舶贝位内岸桥装卸集装箱作业序列;基于装卸作业序列优化方案和INSGA-Ⅱ,提出岸桥最早可作业时间优先的集卡任务指派策略,设计分段式编码及解码方法,求解集卡任务分配与指派问题。通过算例,将设计的算法与常见智能算法进行对比分析,验证了模型与算法的有效性。  相似文献   

8.
在集装箱码头的集港作业中,集卡延迟到港可能导致已制订堆场起重机作业计划变得次优甚至不可行.因此,及时为延迟到港任务更新作业计划具有必要性.考虑集卡到港时间延迟的堆场起重机动态调度问题,基于任务批次分配策略,将调度期划分为多个时段,在每个时段内生成作业计划.以完成时间最短为目标,建立起重机调度混合整数规划优化模型,并提出下界推导模型.提出迭代重优化框架,每当任务延迟到港,就会重优化相应批次的作业计划.在框架内,设计遗传算法求解各批次原有作业计划;设计贪婪插入算法重优化带延迟到港的任务,更新原有计划.实验结果表明,模型、下界推导模型具有正确性和有效性,算法具备良好的求解性能;缩短调度时段长度有利于快速生成起重机作业计划;延迟到港箱量占比越大,作业时间越长,且随着调度时段长度减小,这一影响逐渐弱化.  相似文献   

9.
泊位和岸桥是集装箱码头非常最要的资源,合理的分派与调度可以有效地提高作业效率.目前泊位和岸桥的集成调度模型中大多以最小化船舶在港总时间或最小惩罚成本为目标函数,忽略了码头对船舶服务的公平性.为此,通过扩展现有的连续泊位分配模型,兼顾船舶惩罚成本及船舶等待与岸桥分配的公平性,建立多目标的连续泊位分配模型.设计一个三阶式邻域搜索算法, 该启发式算法包括邻域搜索安排船序列、停泊位置搜索和分配调整岸桥3个阶段.实验结果显示,不同的邻域策略取得的最优解不同,通过设置最优的邻域策略可以获取最优的目标函数值.实验表明,该模型与算法可以在接受的时间内取得最优解,相关成果可以为码头对船舶服务的公平性研究提供理论依据.  相似文献   

10.
非平稳到达的码头集卡预约优化模型   总被引:1,自引:0,他引:1  
针对集货高峰期集卡到达不均而导致的码头严重拥堵问题,运用排队理论和积压后移平稳估计(SBC)方法,通过同时考虑内在的码头服务能力和外在的集卡到达特征制定集卡预约策略.基于闸口、堆场集卡两阶段排队等待时间构建码头集卡预约多目标优化模型,最后用改进的NSGA-Ⅱ算法对模型进行求解.算例结果表明,所构建的模型不仅可以应对集货高峰期时集卡的预约,同时通过优化使得决策天内集卡的平均等待时间得到较大减少且有效均衡了集卡的到达.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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