International Journal of Simulation and Process Modelling (22 papers in press)
- Environment exploration and map building of mobile robot in unknown environment
by Dongshu Wang, Yihai Duan, Jia Wang
Abstract: Simultaneous environment exploration and map building by a mobile robot in an unknown environment are studied. Based on real-time data acquired from a laser sensor, a suitable environment exploration strategy with obstacle avoidance ability is proposed. To handle the problems existing in producing and evaluating candidates, feasible approaches are proposed. They can maximise the expected information gain and keep the environment information integrated, and ensure the environment exploration's continuum and complete traversal. The new evaluation method overcomes the drawbacks of the traditional weighted average method, such as attending to one criterion but losing another. It can comprehensively evaluate the travelling cost, expected information gain and rotating angle to guarantee the quality of the optimal candidate. Furthermore, a topological map model is proposed that uses the nodes of the Growing Neural Gas (GNG) network as the topological network nodes. Through the growing characteristic of the GNG network, new topological nodes are added into the network to abstract and express the holistic knowledge of the surrounding environment and construct the environment map. Simulation results of two different indoor environments demonstrate the effectiveness and feasibility of the approach.
Keywords: mobile robot, environment exploration, map building, GNG network
- Structural optimisation and analysis of internally heat integrated reactive distillation column
by Shoushi Bo, Jian Wang, Lanyi Sun, Fei Bai, Kang He
Abstract: In this contribution, the model for hydrolysis of methyl acetate (MeAc) occurring in an internally heat integrated reactive distillation column (R-HIDiC) was built by using Aspen Plus software. Several configurations of R-HIDiC were proposed. The effects of the configuration on the energy saving were investigated on the premise of ensuring the purity of products and minimum approach temperature. The results reveal that the configuration has significant influence on the performance of R-HIDiC for the hydrolysis reaction of MeAc, and the optimal structure is determined. Sensitivity analysis has also been conducted to tune the design and operating variables of R-HIDiC.
Keywords: internally heat integrated reactive distillation column; configuration; methyl acetate; sensitivity
- Android malware detection based on permission combinations
by Zenghui Liu, Yingxu Lai, Yinong Chen
Abstract: Considering the resource limitations of mobile terminals, such as memory capacity and battery power, it will take a large portion of resources if the complex malicious detection system is implemented in mobile terminals. We propose that the training part is implemented on the backend server and the detecting part is implemented on the mobile terminals. In addition, we apply permission information the applications installed on the terminals, because permission mechanism controls the applications accesses to sensitive information. In our method, we first employ Apriori algorithm to define the permission combinations to be the initial feature and calculate the threat level of permission based on the relative deviation distances. The distances are then used as weights to the classification algorithm. In the process, we apply an integrated feature selection approach based on the principle of self-learning to extract important features to form the feature set. Finally, the minimum-risk Bayes algorithm is introduced to classify unknown applications. The experimental results show that our method is effective on imbalanced datasets.
Keywords: Android, imbalanced datasets, integrated learning, permission-based mechanism
- Engineering-oriented simulation platform for laminar cooling process of hot-rolled strips
by Jinxiang Pian, Zhen Wang, Yunlong Zhu, Tianyou Chai
Abstract: Because the new approach cannot be applied directly in the hot-rolled strip laminar cooling process, a simulation is necessary to verify the new approach effectively, which can improve the strip quality and production yields. In order to make sure the simulation platform is as similar as possible to the practical industrial process, we propose an engineering-oriented distributed simulation platform for the laminar cooling process, integrating part of physical equipment (such as PLC controllers). Additionally, there is an exchange of physical signals among the controller and virtual sensors in the platform. The simulation platform consists of four parts, including virtual object, virtual instruments and actuators, loop controller and process monitoring computer, and setting controller. The virtual object reflects the actual input and output characteristics of laminar cooling process. Virtual instruments and actuators can simulate the field instruments and actuators. Loop controller and process monitoring show the device operating conditions, the control performance, and give alarm signals in time. The setting controller performs setting control procedures. The experimental results indicate that simulation platform has powerful ability to evaluate the new approach in the light of the engineering, which can reduce the live-fire testing cost and meet the requirements of repeat trials.
Keywords: simulation platform; engineering-oriented; laminar cooling process; physical signals exchange
- Customer order fulfilment in mass customization context: an agent based approach
by Khaled Medini
Abstract: The ever-increasing customer-specific needs require suitable strategies to accommodate these requirements and deliver exactly what the customer wants and on time. Mass customisation, as a successor of mass production, is one of these strategies, which aims at satisfying customer needs with near mass production efficiency. However, achieving efficiency is challenged by several issues, such as customer order fulfilment in a customisation environment. In fact, product variety induced by customer choices requires flexible production systems able to manage internal complexity caused by such external variety. This paper proposes a multi-agent based model to manage customer orders by i) defining production requirements of each order, and ii) simulating the execution of the production and delivery operations. It then illustrates the proposed model with a case study and investigates the impact of inventory management on the enterprise economic performance. The case study shows how the model supports the decision-making process with respect to customer order fulfilment.
Keywords: order fulfilment; mass customisation; multi-agent system; dynamic scheduling; performance evaluation; decision making;
- Construction resource scheduling with chaotic particle swarm optimisation
by Zenghui Huang, Hongbo Zhao
Abstract: The traditional methods, such as critical path method and linear programming, have difficulty solving more general scheduling problems, such as resource constrained scheduling problems. Emerging techniques, such as particle swarm optimisation (PSO), have shown advantages in addressing this problem. However, the performance of simple PSO is greatly dependent on its parameters, and bad selection of the parameters often leads to the problem of being trapped in local optima which causes premature convergence. By introducing chaos mapping into the PSO algorithm, we present an updated PSO method addressing the construction resource rescheduling problems. In the proposed approach, the parameters of chaotic PSO have little influence on the performance of the algorithm, and thus make the algorithm more robust. The new method has been examined and tested on a practical problem. The results indicate that the new approach solves the problem at a faster convergence rate and with a better precision, as well.
Keywords: construction management; project management; scheduling; artificial intelligence; particle swarm optimisation
- A virtualisation simulation environment for data centre
by Chia-Jung Chen, Rong-Guey Chang
Abstract: In view of resource efficiency, virtualization is a critical unit to construct a virtualisation data centre (VDC). Indeed, performances bottlenecks are related to low level event. The unpredictability and complexity of virtualisation need to be solved. Generally, using a profiling tool to analyse a layered VDC application remains difficult and error-prone. A possible solution, VDC Simulation Techniques (VST), has been proposed as an alternative tool for early validation and evaluation, instead of using traditional profiling approaches. Although many performance bottlenecks have been indicated, the VST remains elusive. It is because the too many design goal to put in VST. Programmers need a clear VST to have simple programming model, even to solve performance pathologies, including unknown layered in sequence, virtualisation overhead. To address these pathologies, we aim at addressing a missing potential by simulating system from unit simulation to native system implantation for thin simulation. Our proposed simulator is called Data Centre Simulator (DCSim). It first identifies all simulation requirement that can have the VDC behaviour and then preforms a simulation environment by system implantation. Compared with previous research, ours has the following advantages. First, it not only optimises VST and provides cross-layer analysis but also proposes newly adaptive approaches for simulating VDC. Second, unlike discrete event simulation, it has layered situations because it takes real system as simulated unit and then perform system execution. Finally, DCSim provides a simple programming model, because the infrastructure are related to Linux. The results show that ours is more efficient and the analysed results are similar with general VDC.
Keywords: data centre; data sharing; virtualisation.
Special Issue on: "I3M 2013 "Cutting-edge Methodologies, Applications and Technologies in Modelling and Simulation,"
- Military serious game federation development and execution process based on interoperation between game application and constructive simulators
by Changbeom Choi, Moon-Gi Seok, Seon Han Choi, Tag Gon Kim, Soohan Kim
Abstract: This paper proposes a development and execution process for military serious game federation, the Military Serious Game Federation Development and Execution Process (MSGFDEP). The MSGFDEP uses interoperation between an existing game application and constructive simulators to extend the serious game. In order to achieve the interoperation between the game application and constructive simulators, we use a High-Level Architecture (HLA). By interoperating a constructive simulator with an existing game application, a serious game developer can save effort by extending a serious game application, rather than building a serious game from scratch. The proposed methodology comprises two specified processes: federation development and federation execution. When the developer wants to build a serious game from scratch, the proposed methodology supports three specified processes: game loop analysis, game agent design, and development. On the other hand, when the developer wants to organise the federation with existing HLA-compliant serious game and constructive simulators, the methodology provides federation synthesis. Finally, the methodology defines the federation execution process to help trainees to obtain more experiences that are realistic.
Keywords: interoperation; system of systems; constructive simulator; serious game; virtual military training;
- Using the RetSim simulator for fraud detection research
by Edgar Alonso Lopez-Rojas, Dan Gorton, Stefan Axelsson
Abstract: Managing fraud is important for business, retail and financial alike. One method to manage fraud is by detection, where transactions etc. are monitored and suspicious behaviour is flagged for further investigation. There is currently a lack of public research in this area. The main reason is the sensitive nature of the data. Publishing real financial transaction data would seriously compromise the privacy of customers and companies alike. We propose to address this problem by building RetSim, a multi-agentrnbased simulator (MABS) calibrated with real transaction data from one of the largest shoe retailers in Scandinavia. RetSim allows us to generate synthetic transactional data that can be publicly shared and studied without leaking business-sensitive information, and still preserve the important characteristics of the data. We then use RetSim to model two common retail fraud scenarios to ascertain exactly how effective the simplest form of statistical threshold detection could be. The preliminary results of our tested fraud detection method show that the threshold detection is effective enough at keeping fraud losses at a set level, and that there is little economic room for improved techniques.
Keywords: privacy; anonymisation; multi-agent-based simulation; MABS; ABS;
retail store; fraud detection; synthetic data
- An intuitive and efficient approach to integrated modelling and control of three-dimensional vibration in long shafts
by Geoff Rideout, Ahmad Ghasemloonia, Farid Arvani, Stephen Butt
Abstract: Long, slender rotating shafts are susceptible to potentially destructive vibration, the severity of which depends on boundary conditions, geometry, and excitation. Examples of such shafts are truck driveshafts and mine or oilwell drillstrings. A nonlinear three-dimensional bond graph-based shaft model is presented, in which axial, torsional, and lateral vibrations can be predicted. Rigid lumped segments with six degrees of freedom are connected by axial, torsional, shear, and bending springs to approximate continuous system response. Parasitic springs and dampers are used to enforce boundary conditions. Additionally, the shaft can come into contact with surrounding objects. Normal contact forces are generated with a stiff spring, and sliding friction forces during contact are incorporated using coordinate transformations and dynamic Coulomb friction. The model is easily reconfigurable for different boundary conditions, and the bond graph formalism facilitates the inclusion of (semi-)active control submodels such as electromechanical actuators or dampers. The model is applied to an unbalanced rotating 80-metre oilwell drillstring collar section. Thirty segments are sufficient to predict the lowest natural frequencies and static deflection accurately. Simulations show realistic axial, torsional and lateral vibration, with lateral vibration comparable to a finite element model against which preliminary validation is done. Active lateral vibration control is implemented, in which actuators and strain gauges are placed 90-degrees apart around the pipe walls at multiple locations. A proportional controller acting on the strain gauge output significantly attenuates vibration and reduces wellbore contact.
Keywords: multibody dynamics; bond graph; lumped segment; drillstring; shaft vibration
- Bondgraphs model on cavitating pump system
by Kazuhiro Tanaka
Abstract: Cavitation phenomena in a pump unit, as well as internal flows, can be analysed by CFD codes with meaningful precision. However, it is difficult to analyse the dynamic characteristics of cavitating pump systems, such as cavitation compliance and mass flow gain factor. In this paper, the characteristic parameters on pump cavitation are studied through CFD calculations on cavity volume, and the results are related the system Bondgraphs in a lumped parameter system. The cavitation compliance can be represented by 1-port C element and mass flow gain factor can be represented not only by 1-port R element as flow resistance but also by 1-port I element as fluid inertia.
Keywords: Bondgraphs; pump cavitation; dynamic behaviour of pump system; CFD; turbulence model; Rayleigh-Plesset model; cavity volume; one dimensional model; cavitation compliance; mass flow gain factor
- Advanced interoperable simulators for training in car terminals
by Letizia Nicoletti, Alessandro Chiurco, Francisco Spadafora
Abstract: The paper presents a simulation-based training framework for drivers and parkers in car terminals. Before going into the substance of the proposed training system, an analysis of the current procedures used in car terminals as well as of the state of the art has validated the main idea underpinning the research work, confirming the potential benefits of modelling and simulation in such a dynamic and complex environment. The proposed solution, called CTSIM, is made up of three interoperable simulators: an operator simulator, a ship simulator and a vehicle simulator.
The vehicle simulator is able to simulate a medium car or a truck (tractor and trailer) and all the procedures performed by a driver in a car terminal. The operator simulator simulates all the movements and gestures of a parker with a high accuracy thanks to a technical solution including Kinect, a tracking glove and a joystick. The CTSIM simulators are integrated according to the paradigms of distributed and interoperable simulation so as to be able to share the same virtual environment while interacting each other.
Keywords: car terminals, driver training, parker training, simulation
Special Issue on: "I3M 2013 "Modelling and Applied Simulation Multi-Perspective and Multidisciplinary Approaches,"
- An integrated approach for demand forecasting and inventory management optimisation of spare parts
by Mattia Armenzoni, Gino Ferretti, Roberto Montanari, Eleonora Bottani, Giuseppe Vignali, Federico Solari, Marta Rinaldi
Abstract: In this paper, we develop and test an advanced model, based on discrete-event simulation, whose purpose is to forecast the demand for spare parts during the whole lifetime of a complex product, such as an industrial machine. To run the model, the relevant data of the product (i.e., the industrial machine) manufactured by a targeted company should be collected. With those data, the model provides an estimate of the spare parts the company will have to supply during the machine lifetime, and therefore of the optimal level of spare parts inventory the company should keep available. The data provided by the model are subsequently applied to a case example, referring to a hypothetical company, manufacturing industrial plants. The application is carried out considering two scenarios, i.e. a traditional and an advanced approach for demand forecasting, this latter reflecting the circumstance where the company makes use of the proposed forecasting method to estimate the spare parts demand. The comparison of the outcomes obtained in the two scenarios highlights the efficiency and resolution capacity of the model developed. Moreover, from the application, some important considerations are drawn as regards the potential savings that can be achieved by means of an advanced demand forecasting method, such as that enabled by the model developed in this paper.
Keywords: spare parts, simulation, demand forecasting, stock management.
- An agent-based electronic market simulator enhanced with ontology matching services and emergent social networks
by Virgínia Nascimento, Maria João Viamonte, Alda Canito, Nuno Silva
Abstract: AEMOS is a simulator that aims to support the development of agent-based electronic markets capable of dealing with the natural semantic heterogeneity present in this kind of environment. AEMOS simulates a marketplace that provides ontology matching services, enhanced with the exploitation of emergent social networks, enabling an efficient and transparent communication between agents, even when they use different ontologies. The system recommends possible alignments between the agents ontologies, and lets them negotiate and decide which alignment should be used to translate the exchanged messages. In this paper, we propose a new ontology alignment negotiation process, which promotes the reuse and combination of already existing alignments, as well as the involvement of business agents in the alignment composition process. With this new model, we aim to achieve a higher adequacy of the used alignments, as well as a more accurate and trustful evaluation of the alignments.
Keywords: agent mediated e-commerce, agent-based simulation, semantic interoperability, ontology alignment negotiation, ontology alignment evaluation, emergent social networks, social network based recommendations
- Multi-domain modelling and simulation of an automated manual transmission system based on Modelica
by Hua Huang, Sebastian Nowoisky, Rene Knoblich, Clemens Guhmann
Abstract: With the continuous growth in demand for lower emissions and higher riding comfort, the shift quality takes a more and more important role in automated transmission control algorithms. In order to effectively optimise the corresponding control parameters and functions in the transmission control units (TCU), the model-based calibration is a suitable method. For this purpose, a detailed dynamic model, which provides a virtual platform for the shift quality optimisation, is imperative and necessary. In this paper a 5-speed automated manual transmission (AMT) is used as a research object, and a detailed Modelica
Keywords: automated transmission, hydraulic, multi-domain modelling, model-based calibration
- An ontologic agent-based model of recreational polydrug use: SimUse
by Francois Lamy, Terry Bossomaier, Pascal Perez
Abstract: SimUse is an ontology-based social simulation model aiming at reproducing trajectories of recreational poly-drug users. To describe and capture the complexity of this phenomenon, we bring together empirical evidence from ethnography with theoretical constructs from sociology and neuroscience into an agent-based model. After reviewing the context of recreational poly-substance use and justifying our approach, this paper describes the multi-layered structure of the simulation and details some of the key aspects of SimUse. We illustrate the capacity of SimUse to reproduce neurophysiological reactions to substance use and to explore what-if? scenarios related to drug use.
Keywords: polydrug use; agent-based model; social simulation; sociology of deviance
- Dynamic optimal power flow control with simulation-based evolutionary policy-function approximation
by Stephan Hutterer, Michael Affenzeller
Abstract: In current operations research, dynamic optimisation problems are a central and challenging research topic. Especially in complex real-world systems, such as electric power grids, dynamic problems occur where robust solutions need to be found that enable (near-)optimal control over time in volatile as well as uncertain power grid operation. This paper identifies the application of policy-function approximation for such problems. Here, an analytic function is aimed to be found, which takes a state of the dynamic system as input and directly derives control actions that lead to approximate optimal operation at runtime, without the need for embedded optimisation. Applying this approach to two popular and scientifically challenging problem classes in power grids research, this work aims at providing a general view on this optimisation concept. Therefore, a dynamic generation unit control task will be experimentally treated on the one hand, while dynamic load control under uncertainty with electric vehicles represents the second use case. Both applications are related to dynamic stochastic optimal power flow problems, hence, show the successful application of policy-function approximation to this problem domain.
Keywords: simulation optimisation, power flow control, dynamic stochastic optimisation problems, policy-function approximation
- Comparison of optimisation methods tested on testing functions and discrete event simulation models
by Pavel Raska, Zdenek Ulrych
Abstract: The paper deals with the comparison of selected optimisation methods (Random Search, Hill Climbing, Tabu Search, Local Search, Downhill Simplex, Simulated Annealing, Differential Evolution and Evolution Strategy) using various evaluation criteria proposed by us which express the success of the optimisation method in different ways (the success of the method in finding the global optimum, the difference between optimum and local extremes, the distances of quartiles of possible solutions, the number of simulation experiments until the optimum was found). Some of the selected optimisation methods (Downhill Simplex, Simulated Annealing, Differential Evolution and Evolution Strategy) were modified to improve their behaviour to find the global optimum. Optimisation methods were tested on selected testing functions (De Jong
Keywords: simulation optimisation, evaluation criteria, optimisation methods, discrete event simulation models, testing function, ARENA, Plant Simulation, Random Search, Hill Climbing, Tabu Search, Local Search, Downhill Simplex, Simulated Annealing, Differential Evolution, Evolution Strategy
Special Issue on: "Recent Trends in Process Modelling, Simulation and Control,"
- Real-Time Simulation of DEVS Models in CD++
by Gabriel Wainer
Abstract: The CD++ toolkit was developed in order to implement the theoretical concepts specified by the DEVS formalism. The tool allows the execution of both DEVS and Cell-DEVS models. In this work, we present the definition and implementation of a real-time simulator. In such simulations, events must be handled timely and time constraints can be stated and validated accordingly. The new simulation technique allows the interaction between the model and its surrounding environment. Additionally, a non-hierarchical simulation approach is presented and introduced to CD++ in order to reduce the communication overhead.
Keywords: DEVS, real-time DEVS, real-time systems, CD++ toolkit.
Special Issue on: "I3M 2013 Cutting-edge Methodologies, Applications and Technologies in Modelling and Simulation,"
- Production function implementation in an agent-based simulation
by Roman Šperka, Marek Spišák
Abstract: The aim of the paper is to describe the seller-to-customer negotiation in the business processes (sales) of a virtual company. Based on it, we propose an innovative approach to simulate, investigate and predict some of the key performance indicators of a trading company. The methods used to implement the simulation framework in the form of a multi-agent system come out of the agent-based modelling and simulation techniques. The paper firstly presents some of the existing theories about consumer behaviour and the types of factor influencing it. Secondly,the paper characterises a multi-agent model of a virtual company, the agents participating in the seller-to-customer negotiation, and the production function. Finally, the simulation results and their validation are described. To conclude, the proposed approach with the use of seller-to-customer negotiation could properly contribute to better decision-making process of a company's management.
Keywords: system; simulation; virtual company; multi-agent system; negotiation; decision support
- Bond graph-based controller design for the quadruple-tank process
by Matías Nacusse, Sergio Junco
Abstract: The quadruple-tank process has been proposed as a benchmark for multivariable control system design. This paper addresses the design in the bond graph domain of a robust controller having the volumetric flows of two pumps as manipulated variables and the level of the two lower tanks as the regulated outputs. The basic control objectives are expressed in terms of desired closed-loop energy and power-dissipation functions and captured in the bond graph domain by means of a so-called Target Bond Graph. A basic controller design performed via Bond-Graph prototyping yields a primary control law, which is further robustified against parameter uncertainties, measurement deviations and faults using the diagnostic bond graph concept. This results in an additional closed loop consisting of a PI-law, which is represented by a physically meaningful bond graph subsystem. The design methodology is first developed on a simpler two-tank SISO-control problem and then straightforwardly extended to the multivariable problem with the help of some causal manipulations on the four-tank bond graph model.
Keywords: quadruple-tank system, bond graph prototyping, non-linear energy-based control, robust fault-tolerant control
- An advanced training environment for vessels' last mile navigation
by Francesco Longo, Letizia Nicoletti
Abstract: This article presents the results of a research project carried out at Modeling & Simulation Center Laboratory of Enterprise Solutions of the University of Calabria. The project aim was the design, development and prototyping of an advanced training environment for vessel operations in the last mile of navigation. The main idea behind the project is to recreate the typical conditions in which operators are usually involved in a vessel's last mile of navigation: manoeuvres of large ships within the harbour area (executed by ship pilots), tugboat operations to support ship manoeuvres (executed by tugboat pilots), and traffic control executed by officers on the ground (port traffic controllers). The system architecture includes three interoperable simulators, and this article focuses on one of the simulators, the tugboat simulator, presenting the system's general architecture, the software design and development phase, and the hardware integration. In particular, the 3D geometric models and the virtual environments (based on the port of Livorno, Italy) are introduced and described, the tugboat motion equations at sea (based on a six degree of freedom model) and the equations ruling the ship-tugboat interactions are presented and discussed; finally, specific information about the hardware integration (recreation of a tugboat bridge replica) is given. For the sake of completeness, a brief description of the other two simulators (the ship simulator and control tower simulator) and the way such simulators can be used jointly with the tugboat simulator (to provide cooperative training to operators involved in the last mile of navigation) is also given.
Keywords: marine ports, operator training, tugboat pilots, ship pilots, simulation