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This paper describes four design patterns that aim at systematizing and simplifying the modelling and the implementation of multi-level agent-based simulations. Such simulations are meant to handle entities belonging to different, yet coupled, abstractions or organization levels. The patterns we propose are based on minimal typical situations drawn from the literature. For each pattern, we present use cases, associated data structures and algorithms. For genericity purposes, these patterns rely on a unified description of the capabilities for action and change of the agents. Thus, we propose a precise conceptual and operational framework for the designers of multi-level simulations. [ABSTRACT FROM AUTHOR]

Development of intelligent behaviors for vehicles has to cope with rigorous specifications. Many tests are performed for verification, validation and a detailed study of resulting behaviors. In this workflow, testing algorithms with real vehicles is a cornerstone step in developing new intelligent features for future transportation systems. This step requires a lot of experiments before efficiently set up embedded autonomous systems. However, the development of such tests is not linear and it highly depends on external variable factors (weather, hardware or software issues, etc.). To overcome these issues, it is possible to carry out a first series of validation under a simulation framework. In this paper, we describe a simulation platform called VIPS (Vehicles In Platoon Simulator), which provides a virtual environment designed to test and validate platoon control approaches, as close as possible to reality, before bringing them in the real vehicle system. Among the features provided by the simulator, one main contribution is the direct matching between perception and control of both real and virtual vehicles. Moreover, VIPS is also able to deal with perturbations, which are dynamically added to running scenarios so as to reproduce real world conditions. Simulation results in the context of platoon control systems show the benefits of the proposed simulation framework. [ABSTRACT FROM AUTHOR]

This paper details the investigation into the design and control of merging bottlenecks of conveyor-based baggage handling systems, encompassing the merging control algorithm and the impact of the merge’s physical layout. A methodology for the analysis of simulation model results is presented. Results show that the layout of the merge influences bag throughput and when the physical configuration is in a preferred position, input variance has no effect on bag throughput performance. These results have potential application to other material handling systems, such as those used in manufacturing and warehousing. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, new integration methods for stiff ordinary differential equations (ODEs) are developed. Following the idea of quantization-based integration (QBI), i.e., replacing the time discretization by state quantization, the proposed algorithms generalize the idea of linearly implicit algorithms. Also, the implementation of the new algorithms in a DEVS simulation tool is discussed. The efficiency of these new methods is verified by comparing their performance in the simulation of two benchmark problems with that of other numerical stiff ODE solvers. In particular, the advantages of these new algorithms for the simulation of electronic circuits are demonstrated. [Copyright &y& Elsevier]

Abstract: System-level computer architecture simulations create large volumes of simulation data to explore alternative architectural solutions. Interpreting and drawing conclusions from this amount of simulation results can be extremely cumbersome. In other domains that also struggle with interpreting large volumes of data, such as scientific computing, data visualization is an invaluable tool. Such visualization is often domain specific and has not become widely studied and utilized for evaluating the results of computer architecture simulations. In this paper, we introduce our novel interactive visualization tool, called VMODEX, which is developed to support system-level design space exploration of MPSoC architectures. In our tool, the design space is modeled as a tree in which both the design parameters and criteria are shown in a single view. VMODEX is able to handle large design spaces and allows designers to look at the data from different perspectives and at multiple levels of abstraction. Due to the exponential design space in real problems and multiple criteria to be considered, heuristic searching algorithms are often used to trim down a large design space into a finite set of points and provide the designer a set of tradable solutions with respect to the design criteria. In VMODEX, besides the techniques provided for visualizing the DSE results, additional capabilities are developed to understand the dynamic search behavior of heuristic searching algorithms. [Copyright &y& Elsevier]

Abstract: In this paper, we present the PolyMAX module which enhances network simulator 2 (ns-2), the most popular network simulator used in academia, to provide one of the most complete simulation tools to evaluate the performance of Mobile WiMAX networks. PolyMAX is based on the National Institute of Standards and Technology (NIST) module and our specific contributions consist on the design and implementation of the Quality of Service (QoS) classes and QoS management messages, the uplink access grant-request mechanisms, Adaptive Modulation and Coding, and a scheduler handling all five WiMAX QoS classes. We also present validation results for the different components of our module and typical WiMAX simulation scenarios illustrating its flexibility and some of its features. The PolyMAX module represents an important tool enabling researchers to easily implement their Mobile WiMAX scheduling and Adaptive Modulation and Coding (AMC) algorithms and accurately evaluate their performance for realistic scenarios. [Copyright &y& Elsevier]

Abstract: Agent-based distributed simulations are confronted with load imbalance problem, which significantly affects simulation performance. Dynamic load balancing can be effective in decreasing simulation execution time and improving simulation performance. The characteristics of multi-agent systems and time synchronization mechanisms make the traditional dynamic load balancing approaches not suitable for dynamic load balancing in agent-based distributed simulations. In this paper, an adaptive dynamic load balancing model in agent-based distributed simulations is proposed. Due to the complexity and huge time consuming for solving the model, a distributed approximate optimized scheduling algorithm with partial information (DAOSAPI) is proposed. It integrates the distributed mode, approximate optimization and agent set scheduling approach. Finally, experiments are conducted to verify the efficiency of the proposed algorithm and the simulation performance under dynamic agent scheduling. The experiments indicate that DAOSPI has the advantage of short execution time in large-scale agent scheduling, and the distributed simulation performance under this dynamic agent scheduling outperforms that under static random agent distribution. [Copyright &y& Elsevier]

Abstract: Based on traffic data acquisition by the vehicles and inter-vehicle wireless communications, road traffic self-organization has been studied for several years. In this paper we propose a generic model of cooperation among vehicles, which is designed not to saturate the communication medium and to be insensitive to information loss among vehicles. We also propose an original software simulator, which helps us to show how this model can be used in realistic traffic situations. In the simulation, we evaluate one instance of our model, which features an algorithm for limiting the risks of information storms. This feature is particularly interesting in urban settings, where radio communication must fit within the traditional IEEE-802.11 traffic. We show that this algorithm can considerably reduce the amount of communication, without affecting the quality of traffic self-organization. [Copyright &y& Elsevier]

Abstract: This paper presents a digital model algorithm control (MAC) for nonlinear time-delayed systems. The MAC controller is designed based on the sampled-data representation of the dynamic system. A new discretization method using the Taylor series and zero order hold assumption is proposed to discretize the continuous nonlinear time-delayed system. The proposed discretization method can provide accurate time discretization results and convert the discrete-time system into a general nonlinear system, so that the MAC method can be employed. Several simulations are conducted to verify the performance of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper presents an approach to validate WS-CDL documents statically. To deal with those constraints appeared in CDL documents, which cannot be captured by its meta model (XML Schema) totally, we design a machine-based constraint language based on B Method, which uses abstract machines to represent the constraints of the relations among XML nodes. After modelling the constraints, the corresponding checking algorithm can be designed to implement the static validation of CDL documents. Meanwhile, the checking algorithm is integrated into the WS-CDL editor plug-in for Eclipse project. The case studies show that our approach is effective for real examples in practice. [Copyright &y& Elsevier]

Abstract: Ad hoc networks are characterized by fast, dynamic changes in the topology of the network. Introduction of new routing algorithms requires a deep and reliable evaluation process. In this paper, we describe an interactive flexible ad hoc simulator (IFAS) that presents a modern and novel approach to the family of ad hoc simulators. This simulator supports unique viewing, debugging, tuning and interactive capabilities that shorten significantly the design and debug process of new algorithms. The development of the IFAS is ongoing; however, we consider this new simulator as an innovative tool that will supplement traditional simulators. [Copyright &y& Elsevier]

Abstract: This paper presents a review of developed simulated models for a wireless data acquisition system. The system reads analogue information provided by two sensors used for medical purposes. The real data have been recorded by two, pH and pressure sensors used in diagnosing conditions of the esophagus that are employed to examine the system performance. The created model contains four main simulated units using SIMULINK. The first unit contains the output signal, which is encoded to digital signal based on adapting one of the pulse coding modulation (PCM) algorithms. The second unit simulates the processor function that is responsible for framing, mixing and compressing the incoming bit streams from both sensors. The third unit, where the digital data are modulated and sent through different noisy channels, represents an efficient FSK transmitter/receiver model. At the receiver end, the signal is demodulated and processed inversely to extract the original analogue signal read by the two sensors. In this work, the performance of the systems using different PCM methods will be studied comparatively in order to control the transmission and reduce the amount of data frames sent. This will lead to a significant reduction in power consumption. In addition, the performance of the RF unit through additive White Gaussian noise (AWGN) channel was examined by estimating the average bit error rate (BER) for different carrier frequencies. The effect of the multipath fading, inband/outband interference, and adjacent channel power ratio (ACPR) has also been investigated during system assessment. [Copyright &y& Elsevier]

Abstract: In this paper, a stable adaptive fuzzy-based tracking control is developed for robot systems with parameter uncertainties and external disturbance. First, a fuzzy logic system is introduced to approximate the unknown robotic dynamics by using adaptive algorithm. Next, the effect of system uncertainties and external disturbance is removed by employing an integral sliding mode control algorithm. Consequently, a hybrid fuzzy adaptive robust controller is developed such that the resulting closed-loop robot system is stable and the trajectory tracking performance is guaranteed. The proposed controller is appropriate for the robust tracking of robotic systems with system uncertainties. The validity of the control scheme is shown by computer simulation of a two-link robotic manipulator. [Copyright &y& Elsevier]

Abstract: Seeking other joint trajectories of human arm in terms of given trajectory of hand is a wide research problem. In this paper, the computational problem of inverse kinematics of arm movement was investigated. On the basis of an eight-DOF arm model, an inverse kinematics algorithm recreating arm motion was developed in accordance with the human’s feedback control mechanism of motor. In this method, the comfort level, an ergonomic index was adopted as the performance function of the motor control. Through maximizing the comfort level, human arm movement can be simulated when the end-effecter motion is given. This method combines human dynamics and ergonomics. To evaluate the approach, some arm goal-directed movement experiments were carried out. The joint trajectories were predicted with an average R 2 =0.9627 and mean residual error MRE=0.0094m, which indicates that the presented algorithm provides a feasible method to simulate arm goal-directed movement and can be used as an efficient postural manipulation tool for the virtual reality. [Copyright &y& Elsevier]