Seamless simulation

This paper provides a basis for planning, designing, and testing distributed exercises and experiments. Lessons learned from the Synthetic Theater of War--Europe (STOW-E) exercise conducted in November 1994 are incorporated to provide system engineers/integrators areas of consideration in the design and testing of distributed interactive simulation (DIS) exercises and experiments. Issues involving DIS compliance in accordance with IEEE 1278.1, and interoperability and compatibility testing measures are also discussed. Design and test issues for live, virtual, and constructive simulations are considered. This paper assumes basic knowledge of DIS principles.

The Advanced Research Projects Agency (ARPA) has initiated the Synthetic Theater of War (STOW) program to expand the current distributed interactive simulation (DIS) capability to handle larger exercises. Characterizations of the unclassified network traffic from the Synthetic Theater of War-Europe (STOW-E) demonstration are assessed in the context of self-similarity. At small time scales, the LAN traffic oscillates between burstiness and smoothness, whereas the WAN traffic exhibits smoothness. However, both the LAN and the WAN traffic exhibit high burstiness on larger time scales. Therefore, the traffic shows characteristics that would be produced by Poisson-type and self-similar processes. Additionally, in comparing the STOW-E traffic with an asymptotically self-similar process, we find that it has an unusually high Hurst parameter (i.e., H/spl sim/1). A simple mathematical model for the traffic is an uncorrelated process whose parameters vary according to another asymptotically self similar process of high burstiness. Since a combination of self-similar processes results in an asymptotically self-similar process, we conjecture that future STOW traffic should behave as asymptotically modulated self-similar processes.

Wider and brighter are key words when describing the wants of users of projection television (TV). Higher resolution and truer colors also rank high on the list of desirable features. In aircraft flight simulators, there is the need for static, and sometimes dynamic, raster shaping for off-axis projection on large dome screens. To top off these conflicting requirements is the need for time shared calligraphic (stroke writing or vector refresh) and raster TV operation in some computer image generation systems. This paper describes some of the concepts being investigated for such a cathode ray tube (CRT) projector. Problems associated with optics, color convergence, cooling of the CRT faceplates and deflection are discussed. In addition, the problems associated with the side-by-side merging of multiple projectors for very wide field of view projection (Videorama) are addressed.

Evaluating the effectiveness of the Imperial Femoral Intramedullary Nailing Cognitive Task Analysis (IFINCTA) tool in a real-time simulation setting (Distributed Interactive Simulation): a randomized controlled trial

In this paper we propose a distributed control architecture for Distributed Interactive Simulation (DIS) applications which allows for the dynamic integration and communication of interacting processes using intelligent control agents cooperating via a logic communication network. The type of DIS applications which we discuss include the interactive simulation initiative of the US Army to create a realistic warfare training environment by using high speed communications to permit real-time interaction between geographically dispersed warfare simulations with actual combat units in the field, cooperative game playing, and virtual manufacturing. Our architecture, termed Multiple Agent Hybrid Control Architecture (MAHCA), is based on recent advancements in hybrid systems theory and applications. Our approach provides for the flexible interoperability of distributed, real-time information systems by generating, in real time, control programs which comply with logical and evolutionary specifications.

This paper presents a distributed, multi-user virtual reality testbed for a mobile robot. The main components of the testbed include user interface, networking, simulation and robot control. The user interface is implemented as a combination of a virtual environment and a standard graphical user interface (GUI). The virtual environment is developed using the Virtual Reality Modeling Language (VRML) and it corresponds to the laboratory environment where the robot is placed and tested. The standard GUI is implemented using Java Programming language. The World Wide Web (WWW) browser is used to integrate the virtual environment (embedded VRML) and the standard GUI (Java applet) in a single user interface. Users can access a dedicated WWW server and download the user interface. Networking component (communication among users and robots) is implemented using the Distributed Interactive Simulation (DIS) protocol. The existing robot development system has been utilized to provide simulation capabilities. A separate stand-alone Java application has been developed to communicate and control the robot using a wireless Ethernet link. In addition to user's direct control, control algorithms (e.g. fuzzy logic based) can be used to replace the user. A Nomad200 mobile robot has been used for initial measurements and evaluations of the testbed.

The Theater Air Command and Control Simulation Facility (TACCSF) is the world's largest operator-in-the-loop air defense simulation. The facility was originally built by the Office of the Secretary of Defense to study aircraft identification problems in Central Europe. Since 1989, the United States Air Force (USAF) Air Combat Command (ACC) has owned and operated the facility which has been used to support joint service test and evaluation and training. The TACCSF maintains 65 command and control and weapons systems consoles and cockpits which represent key elements of the USAF and Army Integrated Air Defense System (IADS). Each of these devices operate on a common internal network allowing combat-ready crews to "fight" realistic theater-level offensive and defensive scenarios. Extensive data collection, reduction, and analysis capability is available for a wide range of users. The TACCSF has been linked to several joint simulation facilities and live field equipment over wide-band landlines and satellite communications (SATCOM) where scenario objects and events are exchanged using Distributed Interactive Simulation (DIS) protocols. The simulation network, which includes TACCSF, is being used by the USAF to conduct theater missile defense (TMD) analysis and training with emphasis on attack operations; active defense; and battle management, command, control, communications, computers, and intelligence (BMC/sup 4/I).

This paper focuses on Cooperative Adaptive Cruise Control (CACC) in autonomous vehicles. In CACC, vehicles regulate their speed according to a preceding “leader” vehicle in the lane, forming a platoon. In a benign environment, CACC reduces fuel consumption, maximizes road capacity, and ensures traffic safety. However, CACC is vulnerable to various security threats. In this paper, we consider one of the critical threats, where the platoon leader is compromised, and forges acceleration information sent to platoon members. Such attack would lead to traffic instability and potential collisions. First, we propose information sharing in CACC model to allow vehicles and fixed infrastructure to sense and share information about platoon leaders, hence improves the reliability and supports the detection of anomalous behavior. Then, we propose a real-time anomaly detection mechanism that combines statistical learning with the physics laws of kinematics. Specifically, we propose Generalized Extreme Studentized Deviate with Sliding Chunks (GESD-SC) approach, which is applied at each vehicle in the platoon to detect anomalies in real-time based on the vehicle's own speeding decisions. Kinematic model is also utilized to detect unexpected deviations using the leader's information, communicated directly and observed by the leader's neighboring vehicle(s) and/or supporting infrastructure. Combining kinematic model with GESD-SC has shown to be effective in detecting falsification attacks in CACC. Furthermore, we analyze the time performance, and show that the proposed technique outperforms existing method in detection accuracy and processing time.

A series of new Protocol Data Units (PDUs) that send only limited entity-state information over a distributed Interactive Simulation (DIS) network is described. These PDUs are tailored specifically to simulations that model numerous entities rather than simulator modeling a single entity. The use of these new PDUs could (under certain circumstances) realize compression factors of 16, 32, or up to 1200 to one in the amount of data that needs to be sent over a DIS network.

The United States Navy Program Executive Office for Tactical Aircraft Programs is developing an Airborne Tactical Information Management System (ATIMS) capability under the Space and Naval Warfare Systems Command (SPAWAR-32) Real Time Support for Joint Power Projection Advanced Technology Demonstration (ATD) program. The ATIMS project is leveraging modular processing, advanced display and virtual reality technology to demonstrate a capability that provides enhanced flight situation awareness of engagement parameters, exploitation of information for mission alternative selection and more responsive unit level mission planning and rehearsal. The ATIMS project is focused on developing tactical information management and cockpit automation technology to simultaneously reduce pilot workload, reduce system avionics cost, enhance operational flexibility and increase mission effectiveness for air-to-air or air-to-ground combat operations. In a cooperative effort with the Air Force Avionics Directorate, Wright Laboratory (WL/AART-3), the In-Cockpit Mission Replanning and Rehearsal (ICMRR) program is providing ATIMS concept development, long-term master planning and technology demonstration integration support. >

Traffic congestion impacts turn-around-time, productivity, economy and global warming. It is one of the significant challenges the world is facing and hence there is a focused approach to address the same. Parameters-of-significance (PoS) to monitor traffic congestion are identified and research is carried out to define enabling technologies to monitor these PoS. As of now signaling electronics is oblivious of the vehicle densities and their intended direction of travel. Often, the GREEN phase is unutilized as and when no vehicles are traveling in the lane OR the lane ahead has no capacity to accommodate any more vehicles. It is prudent that the un-utilized GREEN phase in both the above opportunity be handed over to the next sequential direction with waiting vehicles. It is also advisable to define GREEN phase proportional to the traffic congestion. The signal timings for different travel directions should be a function of vehicle density. This will also take into consideration the peak and lean traffic directions. This is a first step towards achieving uniform vehicle density. The above can be achieved only if real time data acquisition and computation enables decision making. This paper evolves strategy to improve traffic flow by computing the GREEN phase in real time, taking into account other infrastructural inputs like road quality, number of lanes.

The purpose of this research is to develop an efficient kinematic formulation for an implicit integration method so that relatively low-cost computers can be used for the real-time simulation of multi-body vehicle dynamics models without sacrificing modelling details. The most time-consuming processes associated with the implicit method are the generation and LU decomposition of the system Jacobian matrix of the augmented equations of motion and the constraints at every time step. In order to save the computation time in these processes, a new kinematic formulation is developed to make the system Jacobian remain nearly constant. This allows us to employ a Newton chord method for implicit integration without the need to update the Jacobian. The formulation is motivated by the idea that relative motions between the chassis and other bodies (e.g. suspension components) are limited. Thus, the equations of motion, as well as the joint constraint equations and the generalized force equations, are formulated with respect to the chassis-body reference frame instead of the inertial reference frame. Consequently, the initial Jacobian can be used for long-term vehicle simulation. A comparison of the proposed approach with the conventional approach shows that the proposed approach drastically improved the computational efficiency; i.e. the computational cost of the proposed method was only 35% of the cost of the conventional method. The proposed algorithm yielded almost exact solutions for a prototype multi-body vehicle model run in real time on a 3.5 GHz personal computer.

The models used to simulate an engine, driveline, vehicle, and tire/road-surface models are described. Several control units was linked together to provide a generic real-time hardware-in-the-loop (HITL) simulation is described. The HITL simulation structure and models were designed generically so that they can be utilized for developing a variety of control systems. Generic real-time HITL simulation can use analytical and experimental data, accepts vehicle test parameters as input, and provides real-time, portable dynamic simulation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Graphical programming for real time systems

&lt;p&gt;Many electronic voting systems, classified mainly as homomorphic cryptography based, mix-net based and blind signature based, appear after the eighties when zero knowledge proofs were introduced. The common ground for all these three systems is that none of them works without real time cryptologic calculations that should be held on a server. As far as known, the agent-based approach has not been used in a secure electronic voting system. In this study, an agent-based electronic voting schema, which does not contain real time calculations on the server side, is proposed. Conventional cryptologic methods are used in the proposed schema and some of the requirements of an electronic voting system are constructed within the schema. The schema seems quite secure if the used cryptologic methods and agents are secure. In this paper, proposed schema will be explained and compared with already known electronic voting systems.&lt;/p&gt;