Ship inspection support system using a product model

 Recently, the significance of ship inspections has been increasingly recognized because sea pollution and safety problems are occurring more and more frequently. However, current ship inspections rely on the experience of the workers. Therefore, it is difficult to understand, and hence to improve, the state of ship inspections. In this paper, ship inspection is directed into three stages (plan, do, and check), and the configurations of a total system to support ship inspections are discussed. A prototype system for the “plan” and “do” stages is developed. This is realized by organizing the information that relates to inspection, and defining data models for damage and inspection states. Then the proposed system is integrated with a shipbuilding computer integrated manufacturing (CIM) system so that the ship's structural information can be used effectively. In addition, functions to calculate the damage-finding probability, and functions to generate information about damage and the inspection state are introduced. Therefore, in the planning stage, as inspector can execute a virtual ship inspection, and then the damage-finding probability of each hull part and oversight areas are calculated automatically. Further, by carrying this system into an inspection, an inspector can generate damage information and inspection information simply and easily. Some examples of the proposed system are shown at the end of the paper. Received: November 12, 2001 / Accepted: January 30, 2002     

悬移质泥沙变态模型的沉降相似问题

变态河工模型垂线流速分布是不相似的。以此为基础对悬移质泥沙变态模型的沉降相似问题进行了探讨。结果表明 ,变态模型的泥沙沉降是不相似的     

Delay Restoration of Single-Track Railway Rescheduling

On the basis of analysis of the principle of delay restoration in a disturbed schedule, a heuristic algorithm for rescheduling trains is developed by restoring the total delay of the disturbed schedule. A discrete event topologic model is derived from the original undisturbed train diagram and a back propagation analysis method is used to label the maximum buffer time of each point in the model. In order to analyze the principle of delay restoration, the concept of critical delay is developed from the labeled maximum buffer time. The critical delay is the critical point of successful delay restoration. All the disturbed trains are classified into the strong-delayed trains and the weak-delayed trains by the criterion of the critical delay. Only the latter, in which actual delay is less than its critical delay, can be adjusted to a normal running state during time horizon considered. The heuristic algorithm is used to restore all the disturbed trains according to their critical details. The cores of the algorithm are the iterative repair technique and two repair methods for the two kinds of trains. The algorithm searches iteratively the space of possible conflicts caused by disturbed trains using an earfiest-delay-first heuristics and always attempts to repair the earliest constraint violation. The algorithm adjusts the weak-delayed trains directly back to the normal running state using the buffer time of the original train diagram. For the strong-delayed trains,the algorithm uses an utility function with some weighted attributes to determine the dynamic priority of the trains, and resolves the conflict according to the calculated dynamic priority. In the end, the experimental results show that the algorithm produces ＂good enough＂ schedules effectively and efficiently in disturbed situations.     

Planktonic community structure and carbon cycling in the Arabian Sea as a result of monsoonal forcing: the application of a generic model

The Arabian Sea exhibits a complex pattern of biogeochemical and ecological dynamics, which vary both seasonally and spatially. These dynamics have been studied using a one-dimensional vertical hydrodynamic model coupled to a complex ecosystem model, simulating the annual cycle at three contrasting stations. These stations are characterised by seasonally upwelling, mixed-layer-deepening and a-seasonal oligotrophic conditions, respectively, and coincide with extensively measured stations on the two JGOFS ARABESQUE cruises in 1994. The model reproduces many spatial and temporal trends in production, biomass, physical and chemical properties, both qualitatively and quantitatively and so gives insight into the main mechanisms responsible for the biogeochemical and ecological complexity. Monsoonal systems are typified by classical food web dynamics, whilst intermonsoonal and oligotrophic systems are dominated by the microbial loop. The ecosystem model (ERSEM), developed for temperate regions, is found to be applicable to the Arabian Sea system with little reparameterisation. Differences in in-situ physical forcing are sufficient to recreate contrasting eutrophic and oligotrophic systems, although the lack of lateral terms are probably the greatest source of error in the model. Physics, nutrients, light and grazing are all shown to play a role in controlling production and community structure. Small-celled phytoplanktons are predicted to be dominant and sub-surface chlorophyll maxima are robust centers of production during intermonsoon periods. Analysis of carbon fluxes indicate that physically driven outgassing of CO₂ predominates in monsoonal upwelling systems but ecological activity may significantly moderate CO₂ outgassing in the Arabian Sea interior.     

三维变速拖曳数学模型

分析了水下拖曳系统中拖船机动转弯、变速直航时，水下拖索的受力和运动情况以及水下拖索与拖曳器的相互影响关系，并建立了变速拖曳时，水下拖索的三维数学模型。最后的算例表明该模型具有一定的工程实际价值。     

铁路旅客周转量的改进等维新息模型预测

铁路旅客周转量预测不仅影响铁路客运计划组织工作,它还体现了客运市场中铁路运输的市场控制力。针对灰色模型对数据的要求,采用滑动平均处理和对数化处理原始数据,并采用等维新息模型对铁路旅客周转量进行预测,通过与实际情况和GM(1,1)模型的预测效果的对比可以发现,该模型可以通过检验并且预测效果良好。     

广西浔江长洲枢纽回水长度变化规律研究

水库回水长度解析解在理论上和简单数模理想算例中均得到了验证，但目前尚无实际工程的检验。在介绍分析水库回水长度解析理论的基础上，应用二维水流数学模型，模拟研究了广西浔江长洲枢纽回水长度变化规律，实例验证了回水长度解析理论的正确性。同时，应用解析理论分析了数学模型计算结果的合理性，并分析讨论了两种回水计算方法的关系，以及现实回水计算一般难以观测到回水极值现象原因。计算分析结果表明：回水长度计算的两种方法均具有一定的合理性，有关回水长度变化规律的传统认识是回水长度解析理论的一种特殊情况。     

新型双体船和三体船阻力性能研究

针对小水线面双体船(SWATH)的不足,提出了新型双体、三体船型.通过模型试验方法,对上述船型的阻力性能进行了研究.结果表明,新型三体船由于舯前首中体的设置使得阻力在一定的航速范围内大幅降低;新型双体和三体船型在阻力性能上较SWATH船表现出了一定的优越性.     

表面粗糙度对冰路面上滑动轮胎摩擦牵引力影响的研究

依据能量守恒定律和冰的摩擦熔化理论，考虑冰面和轮胎胎面的表面粗糙度，建立了摩擦界面冰完全熔化条件下轮胎的牵引力预测模型。给出了预测模型中接地胎面温度的选择原则。研究表明，该模型可较好地预测不同条件下轮胎在冰路面上的摩擦牵引力，表面粗糙度的影响随车辆行驶速度的提高而增大。     

近岸波浪数学模型的发展

概要地介绍了国内外平面二维、垂向二维和三维波浪数学模型的研究进展及其应用情况,探讨了波浪数学模型的发展方向。