Analytical models for communication links in emergency management simulation

Emergency response involves the management of several different types of critical infrastructures and resources. Because of the interdependent nature of these systems, it is often very difficult for human decision makers to determine what the second‐ or third‐order effects of their decisions or actions might be. This has resulted in the development of several simulation tools that could be used to evaluate decisions or behaviours and better inform decision makers about the potential impacts of their decisions. One area that remains underdeveloped in this regard is the engagement of communication technologies by human agents, which has the potential to seriously affect delay times in response coordination. Given the size and complexity of simulating the interconnection of heterogeneous systems, developing reduced‐order simulation models has become important to maintain reasonable computation times. This paper describes the derivation of the distribution of the total connection time for a communication link where multiple technologies are engaged. Results show that communication link simulation times, which are among the most time‐consuming simulation routines can be significantly reduced by using the closed‐form distributions.     

Future technology challenges in distributed interactive simulation

The paper examines the changes in computer and communications capabilities over the next 10-15 years which are most likely to affect the central components of distributed interactive simulation (DIS): manned simulators, synthetic environments, and semi-automated forces (SAF). Because these components of DIS are currently very resource intensive, improvements in computer and communications capabilities translate into direct and immediate improvements in DIS capabilities. These improved capabilities in turn allow DIS to contribute in much broader arenas, enhancing troop readiness and reducing system acquisition costs. These improvements will not all come automatically, however. Substantial planning is required to ensure that DIS can take advantage of the coming changes, rather than being overcome by them     

On the validation of system dynamics type simulation models

Simulation models in general and system dynamics type simulation models in particular have become increasingly popular in the analysis of important policy issues in business organizations. The usefulness of these models is predicated on their ability to link patterns of behavior of a system to the underlying structures of the system. Despite their capabilities, the acceptance of system dynamics simulation models by the broader community of modelers and decision makers is limited. We argue that reluctance by the system dynamics modelers to expose their models to formal validity procedures is the main problem. This leads to an exploration of formal validity procedures available but less explored in system dynamics modeling ??repertoire??. An illustration of the application of tests for both the structural and behavior validity of a system dynamics simulation model follows. Finally, some conclusions on the increased appeal for simulation models for the wider community of model builders and users are drawn.     

面向决策支持的数据智能系统研究

为了从自动监控系统的海量数据中准确及时地得到所需的信息,并以直观明晰的图表形式表示出来,以便决策者能够作出快速而正确的判断和决策,给出了数据智能系统(DIS)的构成和定义,分析了DIS的主要研究内容,总结了DIS的企业级应用和研究从MIS到ERP再到业务智能的逐步发展过程,为构建先进的面向决策支持的数据智能系统提供了一种可行的思路。     

DIS today [Distributed interactive simulation]

As the power and potential to create robust distributed interactive simulation (DIS) environments using the technical principles introduced by the SIMNET project gains recognition, the need for establishing standards for the implementation of these principles has grown dramatically. Initially, the interest in achieving interoperability between many disparate simulation components drove the work in developing standards. More recently, an equally important aspect for establishing standards has been to expand the market opportunities for simulation component suppliers. During the past five years, Workshops on Standards for the Interoperability of Distributed Simulations have provided the forum for establishing standards for networking dissimilar simulations to create virtual worlds in which many subjects can interact. These virtual worlds can be used for training individuals, testing equipment, prototyping products, research and development or any application involving the interaction of groups of people in a common synthetic environment     

Thermal simulation of switchgear

In development of low voltage switchgear, proper thermal design becomes more and more important to provide safe function and reliability in spite of miniaturization and increasing performance demanded of modern devices. Due to the high complexity of heat generation and loss processes it is not easy to predict the thermal behavior of devices under various load conditions, i.e., usually numerous tests are required. Rockwell Automation has started thermal simulations of contactors some time ago, and now is working on a three-dimensional (3-D) thermal model of a manual motor controller. This paper describes how to transform well known contact physics into an application oriented thermal simulation. Linking relations of mechanical engineering with contact physics, the influence of the applied tightening torque at the field wiring terminals on the thermal behavior of the device is considered, as well as the modeling of the contact area, taking into account switching arcs during breaking of various load currents. The simulation results are compared with infrared (IR) pictures and thermocouple measurements of existing devices to validate the theory and furthermore reflect its quality.     

多参考点三步搜索法快速稳像算法

针对数字稳像（DIS）算法的实时实现，提出了基于三步搜索（TSS）法和投影算法（PA）的快速DIS算法，并在TSS法的每一步保留多个参考点以提高稳像精度使其更接近于全搜索块匹配法（FS-BM）。仿真实验表明，该算法具有较高的运动估计精度及更快的运算速度，可用于较复杂运动估计模型的实时处理。     

Application of distributed interactive simulation technology withinthe Department of Defense

The paper focuses on distributed interactive simulation (DIS) as an emerging technology which offers new opportunities for the Department of Defense in the design of simulation systems, the approach to training, and the improvement of the material acquisition process. Discussion of these topics is followed by an overview of selected Department of Defense programs that employ DIS. The paper concludes with a brief discussion of technology challenges that must be overcome for this technology to reach its full potential     

Identifying Mechanisms That Highly Accelerated Tests Miss

Extrapolating reliability from accelerated tests for technologies without field data always carries the risk that the accelerated tests do not show the mechanisms which dominate at operating conditions. In statistical terminology, such accelerated testing carries a risk of confounding. For linear models, there is theory which allows one to determine which models are confounded with others. This paper develops analogous theory for a simple kind of confounding model, evanescent processes, when kinetics is used as the basis of modeling accelerated testing. A heuristic for identifying simple evanescent processes that can give rise to disruptive alternatives (alternative models that reverse the decision which would be made based on modeling to date) is outlined. Then, we develop activity mapping, a tool for quantitatively identifying the parameter values of that evanescent process which can result in disruptive alternatives. Finally, we see how activity mapping can be used to identify experiments which help reveal such disruptive evanescent processes     

基于优化决策树的时延敏感流智能感知调度

目前流量调度策略无法做到智能按需化,尤其对于网络突发故障造成的拥塞以及高价值业务的护航场景,无法按需保障时延敏感的业务体验。通过分析研究不同网络业务流量时延敏感性属性需求,探索挖掘不同网络业务流量的行为特征与其时延敏感性需求之间的内在关联关系。然后利用AI技术对这种内在的关联关系进行学习,构建其映射关系,实现了时延敏感流智能感知调度。同时,考虑AI模型的可解释性及可部署性实际问题,采用强化学习剪枝优化可解释性决策树模型,提高模型的鲁棒性同时使模型更轻量化,易于设备部署实现。通过真实网络流量实验,强化学习优化后的决策树模型在单次推理情形下感知正确率提高1.75%,推理速度提升约30%;同时,实验也证明了使用局部微观统计特征多次推理有助于提高模型感知正确率。在所有实验中,强化学习优化的决策树模型规模缩小了60.0%～87.2%,并且Saras比Q-learning具有更好的优化表现。     

Assessing Network Service Profitability: Modeling From Market Science Perspective

Network service providers regularly conduct network planning and upgrade processes to keep their businesses profitable. The effectiveness of a network upgrade/planning decision is intrinsically tied to the ability of a provider to retain and grow its customer population. This paper examines the crucial linkage between network performance, customer satisfaction and profitability of network service, and presents an analytical modeling approach from market science perspective. We derive a generalized forecasting model that projects service profitability from the underlying network service infrastructure and the subscriber population. Through simulation studies and analysis, we show how such approach captures key factors and trends influencing service profitability and how it can significantly improve current network planning and upgrade processes.     

LLC变换器PSPICE仿真的收敛性及参数优化

针对LLC变换器使用PSPICE仿真器进行DC分析和瞬态分析时经常遇到不收敛的问题进行实验,列出了5种有效改进方法。比较了LLC谐振变换器3个参数优化设计的各种方案,提出并验证了运用PSPICE进行多参数优化设计的方法。实验表明,合理运用PSPICE,在谐振开关电源设计中常常会取得比其他方法(软件)更令人满意的效果。     

Intelligent resource simulation for an airport check-in counterallocation system

The objective of resource allocation systems is to assign valuable corporate resources to meet business demands. However, in applications involving stochastic events, demands cannot be determined explicitly beforehand. For those applications, computer simulation is often used to predict resource demands. The paper describes research in developing a knowledge based simulation system to predict resource requirements at an international airport. Our intelligent resource simulation system (IRSS) determines how many check-in counters should be allocated to each departure flight while providing passengers with sufficient quality of service. This predicted resource requirement is then used by a constraint-based resource allocation system to allocate the actual check-in counters. Because IRSS considers many more factors than a human can, the resulting allocation schedule is more efficient. These factors include: 1) different service rates for different destinations, airlines, or handling agents; 2) different passenger arrival rates for different times of the day or days of the week; and 3) different requirements for different service levels, etc. Our experiments show that there are substantial resource savings by combining a resource allocation system with an intelligent resource simulation system     

Cross-layer sensors for green cognitive radio

Green cognitive radio is a cognitive radio (CR) that is aware of sustainable development issues and deals with an additional constraint as regards the decision-making function of the cognitive cycle. In this paper, it is explained how the sensors distributed throughout the different layers of our CR model could help on taking the best decision in order to best contribute to sustainable development.     

Empowering simulation analysis with data-management tools

When engineers engage in simulation studies, they first go through a modeling phase, i.e., the development of a computerized model, and then proceed to an analysis phase, i.e., the repeated execution of the computerized model for a variety of parameters. Since the advent of desktop computing, most simulation studies have relied on processing in interactive mode rather than in batch mode. This paper illustrates how batch processing of analysis activities allows the engineer to focus on drawing conclusions from the simulation experiments instead of wasting time in interactively setting up and conducting the analysis. It is concluded that since batch processing requires additional control capabilities, the analysis power of simulation can be fully realized only when simulation programs are integrated with data management tools     

Finite element modeling in surgery simulation

Modeling the deformation of human organs for surgery simulation systems has turned out to be quite a challenge. Not only is very little known about the physical properties of general human tissue but in addition, most conventional modeling techniques are not applicable because of the timing requirements of simulation systems. To produce a video-like visualization of a deforming organ, the deformation must be determined at rates of 10-20 times/s. In the fields of elasticity and related modeling paradigms, the main interest has been the development of accurate mathematical models. The speed of these models has been a secondary interest. But for surgery simulation systems, the priorities are reversed. The main interest is the speed and robustness of the models, and accuracy is of less concern. Recent years have seen the development of different practical modeling techniques that take into account the reversed priorities and can be used in practice for real-time modeling of deformable organs. The paper discusses some of these new techniques in the reference frame of finite element models. In particular, it builds on the recent work by the author on fast finite element models and discusses the advantages and disadvantages of these models in comparison to previous models     

Fast cycle-approximate MPSoC simulation based on synchronization time-point prediction

In this paper, we propose techniques for fast cycle-approximate multi-processor SoC simulation with timed transaction level models and OS models. Cycle-approximate simulation with an abstract model is widely used for fast validation of a multi-processor SoC in early design stages. However, the performance gain of abstract-level simulation is limited by the overhead of synchronizing multiple concurrent processor/module simulators, which is inevitable in timed simulation. To reduce the synchronization overhead, we adopt the synchronization time-point prediction method, which consists of two phases: static code analysis and dynamic scheduling of synchronizations. In the static analysis phase before simulation, it estimates minimum execution time from every point in the code to the nearest synchronization point. Then, during simulation, it pessimistically predicts the synchronization time-points based on the estimates. The proposed approach targets fast cycle-approximate simulation of a system with delay annotated SW code and transaction level models of HW with dynamic behavior. We present, in this paper, techniques to analyze such abstract models of SW and HW and schedule minimal number synchronizations during cycle-approximate simulation of the models. Experiments show that the approach achieves orders of magnitude higher performance in cycle-approximate multi-processor SoC simulation.