An application of centralized data envelopment analysis in resource allocation in container terminal operations

This paper presents an application of centralized data envelopment analysis (CDEA) to analyse the performance of a number of container terminals supervised by one liner shipping company. It provides a systematic and centralized perspective of resource reallocation based on one company’s perspective. The numerical results show that two of the five dedicated terminals are, by and large, efficient, but the other three need resources to be reallocated. Under the minor adjustment scenario, the liner shipping company should reduce the aggregated amount of the labour cost and the hauling equipment should be transferred to different terminals in America. Under the major adjustment scenario, both the labour and hauling equipment could be reduced.     

Sustainability and interactivity between cities and ports: a two-stage data envelopment analysis (DEA) approach

Ports and cities are intrinsically linked. Port city, which serves as a link between the local and global economy, is an integration of both urban and port systems. Constrained by different regional structures, port cities have developed various formulations over time. Using a two-stage data envelopment analysis (DEA) approach, this paper proposes a new method for measuring the sustainable development of different port city systems. While the previous empirical studies often separate the port system and the urban system, this paper assesses the two systems in an integrated way. Moreover, this paper develops a systematic methodology for measurement of sustainability. Twenty world-leading container port cities are selected for this study using contemporary data. The DEA results display their relative differences in levels of sustainable development, which reveal the effectiveness of the prevailing policies in them. Eventually, recommendations are drawn for other port cities by referring to the best practices.     

Integrating multi-stage data envelopment analysis and a fuzzy analytical hierarchical process to evaluate the efficiency of major global liner shipping companies

In this study, we establish a multi-stage data envelopment analysis model to evaluate the efficiency of global liner shipping companies (LSCs). Because conventional solution procedures cannot guarantee the uniqueness of solutions, in this study, we specifically devise a new two-phase algorithm to overcome this problem. The first phase ranks the priority of all stages by applying fuzzy analytical hierarchical process. The second phase then solves the efficiency score for each stage according to its priority. We established and empirically tested a three-stage research model based on data collected from the Containerization International Year Book, the Alphaliner website and annual LSC reports for the year 2012. The results show that the proposed algorithm not only determines unique solutions for the efficiency scores but also determines the priority order of the stages involved in this process. Taking advantage of the proposed model and algorithm, LSCs can effectively locate bottlenecks in their production processes and further improve them by adjusting the values of the corresponding input and output variables. In addition, the priority order of the stages obtained from the empirical study can also help LSCs allocate their resources.     

小波分析在高桩码头基桩完整性检测中的应用研究

利用反射波法检测高桩码头基桩完整性时,由于基桩存在上部结构,反射波波形会含有干扰信息,变得十分复杂。文章研究了小波分析在高桩码头基桩完整性检测中的应用,利用小波分析消除干扰信号,以减弱梁板等上部结构对基桩检测信号的影响,最后通过具体的工程实例进行了应用验证。     

灌注桩复合缺陷的低应变反射波法检测实例分析

低应变反射波法较易判断桩顶以下首个缺陷,而当灌注桩存在复合缺陷时,因缺陷反射的叠加效应将导致其他缺陷难以识别甚至影响首个缺陷的判断。结合高桩码头灌注桩低应变反射波法检测实例,分析不同类型复合缺陷的反射波曲线特征,研究复合缺陷的识别和检测方法,并提出接桩、拔除外套筒、增加护筒长度及优化泥浆更新方法、凿除桩头等验证及处理措施。     

Optimum arrangement of braces in jacket platform based on strength and ductility

Nonlinear behavior of jacket platforms is important in both design and rehabilitation issues that depends on the bracing arrangement. Both ductility and strength of the structures derived from pushover analysis are highly related to configuration of the braces. Considering a suitable criterion such as constant weight or constant stiffness and period of the structure in all arrangement cases, one can compare the capacity curves and find the best configuration. In this paper a simple logical method for investigating the strength and ductility of the jacket structure is presented, it is shown that global geometry and configuration of the braces are very important and effective in both strength and ductility parameters. Three parameters, normalized strength, normalized ductility and a combination of these two parameters are defined in order to have an engineering and practical index for comparing the results. At the end of the numerical discussion, the optimum configuration can be found. Such an investigation is very important in the initial design stage. Also, in assessment of existing platforms, it is very important to find the reliable strength and ductility of the structure. Such a study gives a deep view of this issue as well.     

船舶海水管路缝隙腐蚀密封性能失效分析及其防护措施

缝隙腐蚀是一种很普遍的局部腐蚀。船舶管路通常在有海水存在的金属之间,以及金属与非金属之间构成的狭窄缝隙内发生腐蚀。B10和HDR双相不锈钢在船舶海水管路使用过程中均出现了不同程度的缝隙腐蚀。文章从腐蚀电化学的某些层面厘清缝隙腐蚀产生的机理,重点针对HDR双相不锈钢缝隙腐蚀实样进行SEM形貌分析和EDS能谱分析,得出缝隙腐蚀的成因和影响因素,并提出若干相应防护措施。     

惠州港水域船舶溢油污染预防的研究

惠州港为珠三角地区重要船载化学危险品港口,面临着严峻的船舶溢油和化学品泄漏污染的威胁,加强惠州港危管防污能力建设,消除安全隐患,杜绝船舶溢油事故发生显得尤为重要。文中着重针对惠州港水域船舶溢油风险与污染防控展开分析论述,并提出相关建议。     

门机臂架纵筋失效对其局部稳定性和动刚度的影响

定量分析箱型结构起重臂下翼缘纵向加劲杆失效对其局部稳定性和动刚度的影响 ,揭示港口门机普遍存在的起重臂受压翼缘板波浪度增大及振动加剧这 2种现象之间的内在联系 ,指出提高其振动基频的有效方法。     

三体船快速性的自航自控船模试验研究

研发了一套自控自航船模数据采集与分析系统,此系统以PAC为核心部件,通过开发的基于VB.NET语言的控制程序,可以实现动力系统和操纵系统的手动与自动执行,并对相关传感器的数据进行同步采集.试验数据用系统辨识的方法进行分析处理.应用此系统对一型三体船进行了快速性试验,并对处理结果进行了简单的比对,表明用此自航自控船模数据采集与分析系统工作可靠,得到的结果准确实用,而且具有良好的发展前景.     

Reliability analysis of a bulk carrier in ultimate limit state under combined global and local loads in the hogging and alternate hold loading condition

The alternate hold still-water loading in hogging combined with wave loading is critical for the safe design of bulk carriers. The ultimate longitudinal strength of the hull girder of bulk carriers in this condition has been found to be considerably reduced by the action of local lateral pressure loads. In the present paper, an interaction equation based on the ultimate hull girder strength assessment obtained by nonlinear finite element analyses is adopted to consider the relationship between ultimate longitudinal bending capacity and average external sea pressure over the bottom. This interaction equation is used as the basis for the failure function. The annual probability of failure is obtained by FORM analysis considering two typical load cases, namely, pure longitudinal hogging bending moment and combined global hogging bending moment and local lateral pressure loads. The effect of heavy weather avoidance on the failure probability is evaluated. The results show that the local lateral pressure has a significant influence on the annual probability of failure of bulk carriers in the hogging and alternate hold loading condition.