A Novel Simulation System Oriented Description Language of Worm Propagation

The popularity of wireless communication networks makes them an attractive target to the creators of worms and other malicious code. Indeed, recently a number of worms designed specifically to spread via these wireless networks have emerged. Based on the epidemic theory, this paper proposes a general model which predicts how a worm propagates through a wireless ad hoc network. Then the differential equations of the model is presented and a necessary condition for worms to spread in these networks is derived, which may be useful in designing a secure wireless ad hoc network. Simulation results show that the process of worm propagation in these wireless networks is sensitive to the deployment density of nodes and the energy consumption of nodes. Therefore, our study can provide insight into deriving a general model to characterize worm propagation in wireless ad hoc networks.

Breaking out of network worms brings a tremendous damage to the Internet. Launch the worm defense and response can improve anti-attack capability of networks. Tracing worm propagation process after its outbreak can reconstruct not only the earliest infected nodes but also the timing order of victims been infected. Based on the improvement of existing offline worm tracing algorithm, we can realize the near real-time tracing for the propagation process of scanning worm: Network traffic data are real-time collected by the detection points from different LANs, then separated into continuous-time detection sliding windows; in every time window, we repeatedly and randomly collect paths that contain worm scanning and infected flow rate, reconstruct path of worm propagation in the current detection window. Results accumulated in sequential detection sliding windows continues doing feedback amendment, real-time reflect the process of worm propagation. we establish a virtual experimental environment of worm propagation and tracing to evaluate the algorithm. Tracing network worm propagation from the initial attack can inhibit continuous spread of the worm, ensure that no more host is infected by the worm, and provide basis for the determination of worm attack origin.KeywordsWormPropagation pathOnline tracingDetection window

Neuro-computational intelligence for numerical treatment of multiple delays SEIR model of worms propagation in wireless sensor networks

Introducing new communication equipment or system to the Tracking and Data Relay Satellite System (TDRSS) ground segment is a complicated process that involves a lengthy development and test cycle. Complexity arises due to the presence of the variety of signaling formats, operation and user constraints, monitor and control parameters, and the requirement to ensure the new piece of ground equipment or system meets the functional and performance requirements for all different combinations of system configuration parameters and operational scenarios. The development cycle starts with extensive software simulations to establish the performance parameters of the new equipment or system followed by a prototyping stage. The prototype system undergoes a battery of tests in a laboratory environment to verify that it is capable of meeting the performance levels derived from the software simulations. Testing must be performed using simulated signals generated either using software or hardware. The current practice is to use a chain of test equipment, each piece in the chain dedicated to a single function. This requires manual setup between different test configurations and test reporting is also handled manually. This is costly both in terms of test hardware investment and the manpower involved. The options available to reduce the cost are to use either a software or hardware simulator that can combine multiple functions in a single unit. Software simulation involves generating signal files that can be played back repeatedly. Depending on the data rate being simulated, each test file can occupy several Terabytes (TBs); in addition, it requires a playback system which tends to be relatively expensive to acquire and maintain. On the other hand, with more advanced signal processing technology the hardware simulation can be achieved with low cost Field Programmable Gate Array (FPGA). A low cost hardware simulator that can support data rates up to 25 Mbps is selected for the simulation system. The simulator supports baseband digital data formats and different modulation and coding schemes used in the TDRSS. Channel impairments applicable for communicating with orbiting platforms and signal impairments generated by the TDRSS itself are also simulated by the system; these include stressing profiles of delay, Doppler, and multipath. Hardware distortions of customer platforms are simulated by a set of software defined distortion filters designed according to the user constraints specified in the Space Network user's guide. In order to reduce the time spent during the prototype testing phase, an automated test system is being developed. Simulator architecture and the test automation approach will be presented.

This paper adopts the High Level Architecture to develop the space-based laser active imaging distribution simulation software system, and designs the system framework which contains three-step workflow including modeling, experimental and analysis. The paper puts forward the general needs of the simulation system first, then builds the simulation system architecture based on HLA and constructs 7 simulation federal members. The simulation system has the primary functions of space target scattering characteristic analysis, imaging simulation, image processing and target recognition, and system performance analysis and so on, and can support the whole simulation process. The results show that the distribution simulation system can meet the technical requirements of the space-based laser imaging simulation.

Passive worms pose threats to mobile P2P(peer-to-peer) networks. To predict the tendency of propagation of mobile P2P passive worms and analyze their behaviors, it is necessary to model mobile P2P passive worm propagation. In this paper, the protocols of mobile P2P networks and the features of passive worm propagation are studied. On the basis, the mathematical model of passive worm propagation is proposed in applying Epidemiology. For the purpose of examining the effect of the mobile P2P-related parameters on worm propagation, simulation experiments are carried out. The results of these experiments show that different parameters have different effect on passive worm propagation, among which the average downloading rate and the average recovery rate of fixed peers have the strongest effect on passive worm propagation among mobile peers.

Simulation and performance evaluation of parallel software on multiprocessor systems

Discrete dynamic simulation models and technique for complex control systems

The Axial Flux BLDC motors are relatively new, specially at higher power ratings over 10 kW. Therefore the designers face a lot of difficulties in designing and optimizing the motor for a given application. This paper presents a new method to optimize the performance in speed, torque, torque stability, power output, power density and motor dimensions in view of the cost and reliability for a given motor; specially to be used for traction purposes. By this method, the motor designers can easily choose the exact parameters of the motor to match the requirement and make sure of the optimization of the design. A software interface and simulation results are presented to check the level of optimization achievable with the system. This paper discusses a three phase axial flux outer rotor BLDC motor, but the core equations can be easily changed to simulate for any kind of motor with the same software and simulation interface.

: This document was prepared under the Task Order Object Oriented C2 Models for the Assistant Secretary of Defense for Command, Control, Communications, and Intelligence (C31), in support of specific requirements identified by Department of the Army, Office of the Chief Information Officer (CIO/G-6). It was performed in response to a task objective to assess the alignment of data representations between representative Army C41 and modeling and simulation (M&S) systems. Interoperability between Command Control Communications Computers and Intelligence (C41) and Modeling and Simulation (M&S) systems is one of the greatest challenges to the M&S community today. Simulations are a cost-effective component of Army force training and provide testing environments for new systems. Simulations fill a void created when exercises are impractical thereby increasing warfighter preparedness. But training on C41 systems requires an interface between these systems and the simulation system. To use simulations with C41 systems the Army has been developing point-to-point software interlaces. These ad hoc interfaces have failed to yield insights into C41/M&S interoperability. Lacking such insights each software interface is a largely independent effort that wastefully re-implements portions of previous interfaces.

The way to speed up the entire process of simulation can be considered from two points of view: the machine side and the human side. The former refers to the use of efficient programming techniques to speed up the simulation program. Specifically, parallel or distributed simulation is the trend, due to the advance of computer hardware technology. The latter refers to the use of intelligent method to automate the whole process of simulation model construction. This paper presents the STNMG system, which is a knowledge-based automatic simulation model generator for public switched telephone networks. Through dialog with its user, STNMG can acquire the necessary information about the simulated system and save it as an internal specification. A time warp optimistic simulator for the simulated system specified by user is then constructed based on this internal specification. The prototype of STNMG is proposed. >

Propagation Delays and Extracellular Potentials. There is increasing evidence that the complex microscopic structure of the myocardium (distribution of cell‐to‐cell connections) plays an important role in determining propagation of excitation in cardiac muscle. To study this phenomenon, extracellular potentials must be measured with microscopic spatial resolution in cardiac tissue. In this article, the relationships between propagation delays across cardiac gap junctions and extracellular potential waveforms are analyzed using a one‐dimensional model of a propagating action potential, for different degrees of cellular coupling. The central question addressed by this study is whether propagation discontinuities at the cellular level can be detected by microscopic resolution extracellular potential measurements, and whether the discrete junctional propagation delay can be measured by extracellular electrodes. Results demonstrate that the discontinuous nature of propagation at the cellular level is reflected as nonuniformities in the local (microscopic) conduction velocity measured by extracellular electrodes with microscopic resolution (interelectrode distance of 50 μm); the degree of nonuniformities in the microscopic velocity is amplified as a result of decreased cellular coupling. These observations are in agreement with recent experimental findings. Propagation time between the middle regions of adjacent cells can be estimated accurately from extracellular potentials at these sites. In contrast, two extracellular electrodes positioned at opposite ends of the gap junction (electrode spacing of 5 μm) cannot detect or measure the propagation delay across the junction. This limitation results from the fact that extracellular potentials do not reflect only the localized underlying electrical sources on such a microscopic scale. As cells become less coupled, irregularities appear in the unipolar extracellular potential waveforms. The simulations relate these irregularities to depolarization of individual cells in the fiber. Under the condition of reduced cellular coupling, the depolarization events of neighboring cells are sufficiently separated in time to appear as separate events in the extracellular waveforms.

An effective simulation mechanism for construction operations

A rapid 3D reproduction system of dam-break floods constrained by post-disaster information

Scientific visualization is a method of computing which provides an insight into the visualized-simulated system. Recently, the simulation of different physical processes and systems has developed. Furthermore, the simulated system getting bigger and more sophisticated. Recently, the authors proposed a new hybrid architecture local area network (Hybrid-Meshnet). The Hybrid-Meshnet allows an insertion of data links into existing LANs. The authors simulate, investigate and visualize the operation and performance behaviour of Hybrid-Ethernet in comparison with conventional Ethernet. Through the event-driven simulation, a computer animation of the network operation is visualized. The simulator, in addition, generates the required data which is displayed as a 3D animated graph for performance investigation. Simulation results indicate that the performance of the Hybrid-Ethernet is improved with respect to the pure Ethernet. Moreover, the visualization technique is very efficient for seeing the unseen through simulation process.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>