Theory and Implementation of Distributed Visual Simulation

The development process as well as the core theory of distributed interactive simulation and high level architecture are discussed, and combined with graphics features, a system of real time distributed visual simulation is established. Based on computer network, simulation platform is built by installing related software and modeling object, and the interactive functions are extended by programming. A set of solutions for building a distributed visual simulation system that include both hardware and software are put forward, and a practical instance is also provided. The whole building process can be summarized into two steps that are scheme consideration and system realization.

Integration of naval distributed tactical training simulation system based on advanced message queuing protocol

Aiming at the problems of unreliable data transmission,poor steadiness,nonsupport of complex data types,direct couple between data transmission and exchange,a high-level method based on advanced message queuing protocol( AMQP) is proposed to integrate naval distributed tactical training simulation system after serious consideration with current information exchange features of military combat system. Transferring layer in traditional user datagram protocol is implemented by publishing and subscribing scheme of message middleware. By creating message model to standardize message structure,integration architecture is formulated to resolve potential information security risks from inconsistent data type and express data transmission. Meanwhile,a communication model is put forward based on AMQP,which is in the center position of the whole transmission framework and responsible for reliably transferring battlefield data among subsystems. Experiments show that the method can accurately post amounts of data to the subscriber without error and loss,and can get excellent real-time performance of data exchange.

Dynamic Multicast Grouping Approach in HLA-Based Distributed Interactive Simulation

In order to improve the efficiency of data distributed management service in distributed interactive simulation based on high level architecture (HLA) and to reduce the network traffic and save the system resource, the approaches of multicast grouping in HLA-based distributed interactive simulation are discussed. Then a new dynamic multicast grouping approach is proposed. This approach is based on the current publication and subscription region in the process of simulation. The results of simulation experiment show that this approach can significantly reduce the message overhead and use fewer multicast groups.

An HLA/RTI Architecture Based on Multi-thread Processing

In order to improve the real-time performance of the real-time HLA(high level architecture) in the application of massive data communication volume,multi-thread processing was adopted,thread pool structure was introduced into the system,different threads to handle corresponding message queues was utilized to respond different message requests.Furthermore,an allocation strategy of semi-complete deprivation of priority was adopted,which reduces thread switching cost and processing burden in the system,provided that the message requests with high priority can be responded in time,thus improves the system's overall performance.The design and experiment results indicate that the method proposed in this paper can improve the real-time performance of HLA in distributed system applications greatly.

Effects of bubbly flow on bending moment acting on the shaft of a gas sparged vessel stirred by a Rushton turbine

The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine,as one of the results of fluid and structure interactions in stirred vessels,was measured using a moment sensor equipped with digital telemetry.An analysis of the shaft bending moment amplitude shows that the amplitude distribution of the bending moment,which indicates the elasticity nature of shaft material against bending deformation,follows the Weibull distribution.The trends of amplitude mean,standard deviation and peak deviation characteristics manifest an "S" shape versus gas flow.The "S" trend of the relative mean bending moment over gas flow rate,depending on the flow regime in gas-liquid stirred vessels,resulted from the competition among the nonuniformity of bubbly flow around the impeller,the formation of gas cavities behind the blades,and the gas direct impact on the impeller when gas is introduced.A further analysis of the bending moment power spectral density shows that the rather low frequency and speed frequency are evident.The low-frequency contribution to bending moment fluctuation peaks in the complete dispersion regime.

Modeling and simulation of torpedo acoustic homing trajectory with multiple targets

The characteristics of a torpedo＇s acoustic homing trajectory with multiple targets were studied. The differential equations of torpedo motion were presented based on hydrodynamics. The Fourth order Runge-Kutta method was used to solve these equations. Derived from sonar equations and Snell＇ s law, a simple virtual underwater acoustic environment was established for simulating the torpedo homing process. The Newton iteration method was used to calculate homing range and ray tracing was approximated by pieccwise line, which takes into consideration distortions cause by temperature, pressure, and salinity in a given sea area. The influence of some acoustic warfare equipment disturb the torpedo homing process in certain circumstances, including decoys and jammers, was alsotaken into account in simulations. Relative target identification logic and homing control laws were presented. Equal consideration during research was given to the requirements of rcal-timeactivity as well as accuracy. Finally, a practical torpedo homing trajectory simulation program was developed and applied to certain projects.

Anaerobic ammonia oxidizing bacteria： ecological distribution, metabolism, and microbial interactions

Anammox （ANaerobic AMMonia OXidation） is a newly discovered pathway in the nitrogen cycle. This discovery has increased our knowledge of the global nitrogen cycle and triggered intense interest for anammox-based applications. Anammox bacteria are almost ubiquitous in the suboxic zones of almost all types of natural ecosystems and contribute significant to the global total nitrogen loss. In this paper, their ecological distributions and contributions to the nitrogen loss in marine, wetland, terrestrial ecosystems, and even extreme environments were reviewed. The unique metabolic mechanism of anammox bacteria was well described, including the particular cellular structures and genome compositions, which indicate the special evolutionary status of anammox bacteria. Finally, the ecological interactions among anammox bacteria and other organisms were discussed based on substrate availability and spatial organizations. This review attempts to summarize the fundamental understanding of anammox, provide an up-to-date summary of the knowledge of the overall anammox status, and propose future prospects for anammox. Based on novel findings, the metagenome has become a powerful tool for the genomic analysis of communities containing anammox bacteria; the metabolic diversity and biogeochemistry in the global nitrogen budget require more comprehensive studies.

Sphalerite/silica interaction:Zeta potential distribution measurement

An appropriate measurement is needed to control the calcium ion content and reduce the interaction among fine mineral particles.In this paper,the sphalerite/silica interactions were studied by Zeta potential measurements and a novel Zeta potential distribution（ZPD）measurement method in different concentrations of calcium ion solution.To study mineral surface molecular and atomic absorption states,energy dispersive spectroscopy（EDS） and scanning electron microscope（SEM） were used.Flotation reagent adsorbed on the mineral surface was analyzed by the interactions status.The results show that adsorption of flotation reagent is not conducive when the calcium ion concentration is high in the solution.Reducing the calcium ion concentration is the effective method to reduce particle interactions in the pulp.The specific method is that the appropriate amount of sodium carbonate is added into the gypsum-supersaturated solution.The minerals＇ interactions can be interpreted by measuring ZPD.