cationEducation and VocationEducatio

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Distributed and Redundant Design of Ship Monitoring and Control Network

The world trend in ship automation is to integrate the monitoring, intelligent control and systematic management of the instruments and equipments both on bridge and in engine room. The paper presents a design scheme of the ship integrated monitoring and operating system based on two layers distributed and redundant computer network. The lower layer network is the field bus network connected mainly by CAN bus; the upper one is the PC local network in TCP/IP protocol, which consisted of a database server, monitoring and operating computers, industrial computers and a set of switches. Distributed schemes are fully applied to both software and hardware. This paper specifically describes the composition, software distribution and redundant technology of the upper local network and gives some important sample codes for the implement of the redundant and distributed design. The technologies here have been proved in the many applications and it may be applied to other industrial fields.     

Evaluation and selection of the ship collaborative design resources based on AHP and genetic and simulated annealing algorithm

1Introduction Theshipdesigninvolvesshipyards,ship owner,classi ficationsociety,shipresearchinstituteandsoon,while theshipcollaborativedesignneedsthecooperationbe tweenthedesignersfromdifferentdepartmentsand thosewithdiverseknowledge.Thus,intheshipcollab o…     

Analysis and Comparison of Range-Range Positioning Mode and Hyperbolic Positioning Mode

Three key factors are discussed, which affect positioning accuracy of range-range positioning mode and hyperbolicpositioning mode.Based on the error elliptical theory, the expressions of positioning error and of positioning geometric factor ofrange-range positioning mode and hyperbolic positioning mode are derived, and the positioning error and the blind positioningarea of two different positioning modes are analyzed. According to the requirement of navigation area, an optimum positional     

Wetlands preservation and management: A rejoinder‐economics,science and beyond

Note

This article is a short response to a critique by William Odum and Stephen Skjei of an earlier article by this author in this Journal entitled “Wetlands Preservation and Management on Chesapeake Bay: The Role of Science in Natural Resource Policy.”; It is a continuation of themes begun in that paper. It focuses on the question of determining the social value of wetlands preservation and the contradictory positions which ecologists fall into when discussing the value of wetlands.     

The process analysis and improvement of the slender and flat shaft of track recorder

1Introduction Thetrackrecorderisanimportanttechnicalinstru mentsproducedforamarineship.Itisusedforreal timedrawingofaship’scourse.Thecontrolsystemof thetrackrecorderisanopenloopsystemdrivenbya step by stepmotor,sotheprecisionofthetransforma tionpartdirec…     

Research on vibration and near-field soundradiation of ring-ribbed cylindrical shell coated deadening and decoupling materials

The research on structural vibration and sound radiation of underwater ring-ribbed cylindrical shell, which is coated with a kind of deadening and decoupling materials, becomes a focus in recent years. This paper analyzes the problem on two aspects: model experiment and numerical calculation. The model experiment is carried out including three cases firstly, in which the structural vibration response and radiating acoustic field are measured respectively, and the results gained in these three cases are analyzed to discuss the effect of reducing structural vibration and radiating noise of the deadening and decoupling materials. The coupling FEM/BEM and the SEA methods are both used in numerical calculation, i.e. the arithmetic of the coupling FEM/BEM method is adopted to calculate the low frequency characteristics and the SEA method is adopted to calculate the medium-high frequencies characteristics of the model. By comparing experimental results with numerical calculation results, it is proved that the algorithm adopted in this paper is reasonable.     

河海大学Water Science and Engineering创刊

国家新闻出版总署日前正式批复，同意河海大学创办英文期刊Water Science and Engineering（水科学与水工程）。该刊为季刊，面向国内外公开发行，国内统一连续出版物号为：CN32—1785／TV。     

Building both friendship and trade bridges

The POrt Of BQSton 15 NeW巨ngland,S major full serviee Portand gatewayfor trade,aeeounting for aP-Proximatelyg,000」obsandeontributinganestimated$8 billion to the了egionaleeonomy ofthe NortheastUnitedstates. Thesix一stateNew Englandregion 15made uP ofthestatesof Mas3aehusetts,Conneetieut,Rhode lsland,Maine,NewHamPshire,and论rmont.New Englandlseonsideredto be oneof the mostafflUentregionsin the USA.The Port of Bostonhas a strong lmPort and exPortmarketwithaPProxirnately 60%of New…     

Simulation and analysis of breechblock mechanism

1Introduction Intheshootingsystemofthenavalgun,therequire mentforthemotionaccuracyofitsmechanismisstrict inmanufacturingandassembling.Butthemechanism ofthewarshipgunmovesto and froatahighvelocity,theimpactsbetweensomepartsinfluencetheaccuracy ofthemotionb…     

Navigator and diplomat Zheng He remembered

The year 2005 witnesses a number of large-scalecommemorative activities to celebrate the great navigator anddiplomat Zheng He (1371-1435) all over the country. Widelyconsidered to be an important person in the history of Chinesenavigation, Zheng He led hi…     

Review and pros-pects ofr China''''s economy

The Chinese economy grew 8 per cent in 2002. The speedy growth of China's economy in 2002 was fuelled by booming exports and the central government efforts to stimulate domestic demand. Preliminary figures from the National Bureau of Statistics suggest that the country's gross domestic product (GDP) reached 10.2 trillion yuan (US$1.23 trillion) in 2002, an increase of 8 per cent from the previous year. 2002 is a year for which we have a whole host of things to rejoice over, to remember, and to toast. The momentous 16th National Congress of the Communist Party of China, which selected a new leadership for our country, was the biggest event on China's     

Cooperative path following control of UAV and USV cluster for maritime search and rescue北大核心CSCD

［Objectives ］ This paper studies a three-dimensional (3D) cooperative path-following control problem in the process of maritime search and rescue for a heterogeneous unmanned cluster system composed of unmanned aerial vehicles (UAVs) and unmanned surface vehicles (USVs).［Methods ］ First, kinematic models of the UAVs and USVs are established under a fixed coordinate system and body coordinate system. In order to design a 3D path-following controller suitable for motion control, an air coordinate system is established, and the path tracking error models of the UAVs and USVs are established in the Serret-Frenet coordinate system. Next, a 3D line-of-sight (LOS) guidance law is designed at the kinematic level, and a cooperative path-following control method suitable for heterogeneous clusters of marine vehicles is proposed, allowing the UAVs and USVs to track the preset parameterized path. Finally, the stability of the control system is analyzed based on the Lyapunov stability theory.［Results］The simulation results verify the effectiveness of the proposed cooperative path-following control method for heterogeneous clusters of marine vehicles.［Conclusions］The results of this study can provide references for maritime search and rescue by using the proposed cooperative path-following control method. © 2022 Journal of Clinical Hepatology. All rights reserved.     

Asian Economic Recovery and Chinese Economic Acceleration

The economies of the Asian region have recovered quickly since the second half of 1999, and the sphere of recovery is extending further. Financial market confidence returns in most economies that have been affected by the crisis. It is shown by not only the powerful export, but also the growth of domestic demand and intra-regional trade and the industry of both service and real estate begin to bottom out, etc. In the field of macro-economic control, Asian countries have made remarkable achievements in     

Problems and measures after China''''s WTO entry

China's accession to the World Trade Organization (WTO) will not only benefit the country's economic development, but also have far-reaching influences on Chinese society, pointed out a report released by the Development Research Centre under the State Council at a recent forum. WTO membership will accelerate the modernization of Chinese society and have a positive effect on people's lives. However, it may also exacerbate some existing problems such as unemployment and the widening gap between social classes, said the report. The government is urged to draft specific laws and policies to deal with coming challenges, ease potential social conflicts and     

SPSM and its application in cylindrical shells

In naval architectures, the structure of prismatic shell is used widely. But there is no suitable method to analyze this kind of structure. Stiffened prismatic shell method (SPSM) presented in this paper, is one of the harmonic semi-analytic methods. Theoretically, strong stiffened structure can be analyzed economically and accurately. SPSM is based on the analytical solution of the governing differential equations for orthotropic cylindrical shells. In these differential equations, the torsional stiffness, bending stiffness and the exact position of each stiffener are taken into account with the Heaviside singular function. An algorithm is introduced, in which the actions of stiffeners on shells are replaced by external loads at each stiffener position. Stiffened shells can be computed as non-stiffened shells. Eventually, the displacement solution of the equations is acquired by the introduction of Green function. The stresses in a corrugated transverse bulkhead without pier base of an oil tanker are computed by using SPSM.     

Review and pros pects for China economy

The Chinese economy grew 8 per cent in 2002. The speedy growth of China‘s economy in 2002 was fuelled by booming exports and the central government efforts to stimulate domestic demand.     

Inland container terminal—function and rationale

Increasing commercial and recreational pressures on urban waterfront lands, growing demand by seaports for back-up areas and changes in cargo-distribution concepts have caused the relocation of several port functions and the establishment of inland container terminals.     

Joining the WTO and hosting the 2008 Olympic Games----the two events should anchor China''''s stability and reform

What drives a country is mostly its national psyche. China's jubilation in winning the 2008 Olympic Games should be viewed in relation to the Chinese psyche. For the first time, the globe's greatest sports event will be brought to the world's most populous country. The successes in economic development over the past two decades have greatly lifted Chinese people's expectations about what is possible. They