Computer generated imagery for training simulators

The need for visual simulation as part of a training simulator is restated. The characteristics of a visual system are discussed leading to the specification for a computer generated image system, which is described and the information flow through each section discussed. Some features such as texture, shading, edge smoothing and transparency are singled out for special attention and finally the subject of model database preparation is briefly covered.     

Object structures for real-time systems and simulators

The market for real-time applications has grown considerably in years, and in response engineering methods have also improved. Today's techniques, while adequate for building moderately complex embedded applications, are inadequate for building the large, highly reliable, very complex real-time applications that are increasingly in demand. To build such large systems, engineering teams need a more uniform, integrated approach than is available today. Ideally, the development approach would make uniform the representations of both application environments and control systems as they proceed through various system engineering phases. The ideal representation (or modeling) scheme should be effective not only for abstracting system designs but also for representing the application environment. It should also be capable of manipulating logical values and temporal characteristics at varying degrees of accuracy. This ideal modeling scheme is not likely to be realized through conventional object models. Although they are natural building blocks for modular systems, conventional object models lack concrete mechanisms to represent the temporal behavior of complex, dynamic systems. This article describes a real-time object structure that can flexibly yet accurately specify the temporal behavior of modeled subjects. This approach supports strong requirements-design traceability, the feasibility of thorough and cost-effective validation, and ease of maintenance     

某飞行训练模拟器飞行轨迹绘制

GDI+(图形设备接口)是Windows操作系统的一个子系统,它把Windows中关于绘制图形的API函数封装在一组类中,在一种与设备无关的环境下提供了一套统一的绘图编程模型,利用GDI+可方便快捷地实现应用程序与图形设备的交互.飞行模拟器的飞行轨迹为教员提供了直观的飞机位置显示,结合某型飞行模拟器的研制,采用GDI+,通过先在内存建立一块"虚拟画布",然后将需要画的图形先画在这块"虚拟画布"上,最后再一次性将整块"虚拟画布"画到真正的窗体上这样的"双缓冲"技术,在Visual C#.Net下对飞行模拟器的飞行轨迹进行了绘制.     

Productivity analysis simulators for multi-job and batching type equipments

A number of generalized simulation models are described which can analyze operator productivity and product turn-around-time on multi-job and batching type equipment. Based on demand on these types of equipment, it simulates equipment utilization and generates product turn-around-time with and without scheduling the equipment at different time intervals within scheduled shift or day. The models allow maximum capacity to be utilized per each equipment-run depending on work-in-process available in front of the equipment. The models give the industrial engineer the capability to estimate operator requirements for a given demand and equipment. They also provide him decision making capability to evaluate different scheduling intervals and resulting productivity increments for a given equipment. He then can analyze these productivity increments and resulting increase in turn-around-time and work-in-process. This leads him to make rational decisions as to how much work-in-process he should allow in front of the equipment in order to gain productivity increases with satisfactory turn-around-time. Both models are written in GPSS-V language. The models allow for plots up to ten points on productivity vs turn-around time curve for each simulation-run.     

分布式仿真训练系统通用开发框架研究

针对当前复杂分布式仿真训练系统在开发过程中存在着大量重复工作的问题,在分析其共性特征的基础上,提出了一套适用于分布式仿真训练系统的通用开发框架。该框架采用基于HLA的分布式结构,包含岗位训练软件开发框架、训练指挥台开发框架、三维场景显示开发框架和一个数据库系统,满足共性特征。详细阐述了通用开发框架的软件架构、通用功能类库和自动化科目生成器。描述了使用该框架进行仿真训练系统开发的一般流程。实际应用表明,该框架不仅能够大大减少重复的开发工作,而且统一的软件架构也有利于系统的维护。     

电动负载模拟器的重复控制器的设计

通过分析电动负载模拟器的基本结构和工作原理,建立数学模型并且分析了多余力矩产生的机理,提出一种重复控制和PID控制相结合的复合控制策略,利用重复控制改善系统的稳态特性,利用PID控制改善系统的动态特性.仿真结果表明,所采用的方控制方法能够有效地抑制多余力矩,提高了系统的稳态精度和动态性能.     

New generation of microsystem simulators

A novel type of microsystem simulator is described which allows a system designer to tailor the simulator to his application. Simulation of I/O, real-time events, and additional hardware (which may contain other processors) is possible, which is not the case for most existing simulators.     

Model-based predictive motion cueing strategy for vehicle driving simulators

Motion-based driving simulators are designed to render accelerations perceived as realistic, while keeping the motion system within its physical limits. These objectives are generally contradictory, and consequently motion control strategies are difficult to customize for different simulator configurations. In this paper, a novel approach is presented for the design of motion rendering strategies, using the model-based predictive control theory. Compared to traditional cueing techniques, actuator constraints are always respected, and the use of motion workspace is maximized during simulations. Models of human motion perception can be integrated to reduce sensory conflicts. A practical implementation on a high-performance automotive driving simulator is presented.     

ATABS: A technique for automatically training agent-based simulators

The automatic training of agent-based simulators can be a complex task because of (a) their common nondeterministic behavior and (b) their complex relationships between their input parameters and the outputs. This work presents a technique called ATABS for automatically training agent-based simulators. This technique is based on a novel mechanism for generating random numbers that reduces the variability of the global results. This work provides a framework that automates this training by considering the relationships between the simulation parameters and the output features. This technique and framework have been applied to automatically train two different simulators. The current approach has been empirically compared with the most similar alternative. The results show that ATABS outperforms this alternative considering (1) the similarity between simulated and real data and (2) the execution time in the training process. The ATABS framework is publicly available. In this way, it ensures not only the reproducibility of the experiments, but also allows practitioners to apply the current approach to different agent-based simulators.     

Computer image generation for flight simulators: the Gabor approach

A formalism for image representation in the combined frequency-position space is presented using the generalized Gabor approach. This approach uses elementary functions to which the human visual system is particularly sensitive and which are efficient for the analysis and synthesis of visual imagery. The formalism is also compatible with the implementation of a variable resolution system wherein image information is nonuniformly distributed across the visual field in accordance with the human visual system's ability to process it. When used with a gaze-slaved visual display system, imagery generated using the techniques described here affords a combination of high resolution and wide field-of-view. This combination is particularly important in high-fidelity, computergenerated, visual environments as required, for instance, in flight simulators.     

Behavioural factors influencing the use of flight simulators for training

The case for using flight simulators as a training aid is propounded, and the drawbacks of training entirely in flight are listed. Transfer of learning from the simulated to real-life situation is discussed with relevant examples. A diagram illustrating the relative cost of using different types of simulator is given, and recent research is discussed. Finally, the attitude and influence of the organisation to simulator, trainee and instructor is described.     

Dynamical properties of hybrid systems simulators

This paper analyzes the dynamical properties of a class of hybrid systems simulators. A hybrid system is a dynamical system with a state that can both flow and jump. Its simulator attempts to generate its solutions approximately. The paper presents mild regularity conditions on the hybrid system and its simulator to guarantee that simulated solutions are close to actual solutions on compact (hybrid) time intervals, and that asymptotically stable compact sets are preserved, in a semiglobal practical sense, under simulation. In fact, it is established that asymptotically stable compact sets are continuous in the integration step size parameter of the simulator; that is, as the step size of the simulator converges to zero, the asymptotically stable set observed in simulations approaches the asymptotically stable compact set of the true hybrid system. Examples are used to illustrate concepts and results.     

电动负载模拟器的研究进展

简要叙述了研究电动负载模拟器的必要性,介绍了目前国内外电动负载模拟器的研究情况,以及应用于负载模拟器的典型控制方法,并分析了它们的特性,结构简单、体积小、成本低,具有小信号跟踪能力强,加载分辨率高,特性稳定,集成度高适合试验研究,成为新型负载系统的探索研究方向.     

Efficient use of commercial electromagnetic simulators for microwave and millimeter-wave circuits

Efficient use of electromagnetic simulators is accomplished by classification of EM problems into three categories—characterization of circuit elements, optimization of circuit elements, and creation of circuit element libraries. Real circuit examples in each of the three categories are given to demonstrate the practical aspects of efficient EM simulations and the computer resources required. © 1995 John Wiley & Sons, Inc.     

Open-source simulators for Cloud computing: Comparative study and challenging issues

Resource scheduling in infrastructure as a service (IaaS) is one of the keys for large-scale Cloud applications. Extensive research on all issues in real environment is extremely difficult because it requires developers to consider network infrastructure and the environment, which may be beyond the control. In addition, the network conditions cannot be controlled or predicted. Performance evaluations of workload models and Cloud provisioning algorithms in a repeatable manner under different configurations are difficult. Therefore, simulators are developed. To understand and apply better the state-of-the-art of Cloud computing simulators, and to improve them, we study four known open-source simulators. They are compared in terms of architecture, modeling elements, simulation process, performance metrics and scalability in performance. Finally, a few challenging issues as future research trends are outlined.